[PATCH v3 00/14] tcg/ppc: direct branching, power9, power10

[PATCH v3 00/14] tcg/ppc: direct branching, power9, power10

[Richard Henderson]

Supercedes: 20230808030250.50602-1-richard.henderson@linaro.org
Supercedes: 20230815050117.34731-1-jniethe5@gmail.com

Build on Jordan's patch to allow direct branching and USE_REG_TB
to co-exist.  Use the power9 addpcis wherever pc-relative addrs
might be handy.  Merge in my power10 patches for prefixed insns.

Finish up with an RFC to disable TCG_REG_TB for power9+, when
pc-relative code sequences exist.  I've only lightly tested this,
and it seems to increase code size by a few insns per TB.  It
really depends on how much we end up using the constant pool.

What is needed is to determine if !TCG_REG_TB helps.  If it doesn't,
then some of these patches could be dropped as unreachable.


r~


Jordan Niethe (1):
  tcg/ppc: Enable direct branching tcg_out_goto_tb with TCG_REG_TB

Richard Henderson (13):
  tcg/ppc: Untabify tcg-target.c.inc
  tcg: Add tcg_out_tb_start backend hook
  tcg/ppc: Reinterpret tb-relative to TB+4
  tcg/ppc: Use ADDPCIS in tcg_out_tb_start
  tcg/ppc: Use ADDPCIS in tcg_out_movi_int
  tcg/ppc: Use ADDPCIS for the constant pool
  tcg/ppc: Use ADDPCIS in tcg_out_goto_tb
  tcg/ppc: Use PADDI in tcg_out_movi
  tcg/ppc: Use prefixed instructions in tcg_out_mem_long
  tcg/ppc: Use PLD in tcg_out_movi for constant pool
  tcg/ppc: Use prefixed instructions in tcg_out_dupi_vec
  tcg/ppc: Use PLD in tcg_out_goto_tb
  RFC tcg/ppc: Disable TCG_REG_TB for Power9/Power10

 tcg/tcg.c                        |   3 +
 tcg/aarch64/tcg-target.c.inc     |   5 +
 tcg/arm/tcg-target.c.inc         |   5 +
 tcg/i386/tcg-target.c.inc        |   5 +
 tcg/loongarch64/tcg-target.c.inc |   5 +
 tcg/mips/tcg-target.c.inc        |   5 +
 tcg/ppc/tcg-target.c.inc         | 280 ++++++++++++++++++++++++++-----
 tcg/riscv/tcg-target.c.inc       |   5 +
 tcg/s390x/tcg-target.c.inc       |   5 +
 tcg/sparc64/tcg-target.c.inc     |   5 +
 tcg/tci/tcg-target.c.inc         |   5 +
 11 files changed, 288 insertions(+), 40 deletions(-)

-- 
2.34.1

[PATCH v3 01/14] tcg/ppc: Untabify tcg-target.c.inc

[Richard Henderson]

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 tcg/ppc/tcg-target.c.inc | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/tcg/ppc/tcg-target.c.inc b/tcg/ppc/tcg-target.c.inc
index 511e14b180..642d0fd128 100644
--- a/tcg/ppc/tcg-target.c.inc
+++ b/tcg/ppc/tcg-target.c.inc
@@ -221,7 +221,7 @@ static inline bool in_range_b(tcg_target_long target)
 }
 
 static uint32_t reloc_pc24_val(const tcg_insn_unit *pc,
-			       const tcg_insn_unit *target)
+                               const tcg_insn_unit *target)
 {
     ptrdiff_t disp = tcg_ptr_byte_diff(target, pc);
     tcg_debug_assert(in_range_b(disp));
@@ -241,7 +241,7 @@ static bool reloc_pc24(tcg_insn_unit *src_rw, const tcg_insn_unit *target)
 }
 
 static uint16_t reloc_pc14_val(const tcg_insn_unit *pc,
-			       const tcg_insn_unit *target)
+                               const tcg_insn_unit *target)
 {
     ptrdiff_t disp = tcg_ptr_byte_diff(target, pc);
     tcg_debug_assert(disp == (int16_t) disp);
@@ -3587,7 +3587,7 @@ static void expand_vec_mul(TCGType type, unsigned vece, TCGv_vec v0,
                   tcgv_vec_arg(t1), tcgv_vec_arg(t2));
         vec_gen_3(INDEX_op_ppc_pkum_vec, type, vece, tcgv_vec_arg(v0),
                   tcgv_vec_arg(v0), tcgv_vec_arg(t1));
-	break;
+        break;
 
     case MO_32:
         tcg_debug_assert(!have_isa_2_07);
-- 
2.34.1

[PATCH v3 02/14] tcg: Add tcg_out_tb_start backend hook

[Richard Henderson]

This hook may emit code at the beginning of the TB.

Suggested-by: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 tcg/tcg.c                        | 3 +++
 tcg/aarch64/tcg-target.c.inc     | 5 +++++
 tcg/arm/tcg-target.c.inc         | 5 +++++
 tcg/i386/tcg-target.c.inc        | 5 +++++
 tcg/loongarch64/tcg-target.c.inc | 5 +++++
 tcg/mips/tcg-target.c.inc        | 5 +++++
 tcg/ppc/tcg-target.c.inc         | 5 +++++
 tcg/riscv/tcg-target.c.inc       | 5 +++++
 tcg/s390x/tcg-target.c.inc       | 5 +++++
 tcg/sparc64/tcg-target.c.inc     | 5 +++++
 tcg/tci/tcg-target.c.inc         | 5 +++++
 11 files changed, 53 insertions(+)

diff --git a/tcg/tcg.c b/tcg/tcg.c
index ddfe9a96cb..1e9b7433bb 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -108,6 +108,7 @@ static void tcg_register_jit_int(const void *buf, size_t size,
     __attribute__((unused));
 
 /* Forward declarations for functions declared and used in tcg-target.c.inc. */
+static void tcg_out_tb_start(TCGContext *s);
 static void tcg_out_ld(TCGContext *s, TCGType type, TCGReg ret, TCGReg arg1,
                        intptr_t arg2);
 static bool tcg_out_mov(TCGContext *s, TCGType type, TCGReg ret, TCGReg arg);
@@ -6009,6 +6010,8 @@ int tcg_gen_code(TCGContext *s, TranslationBlock *tb, uint64_t pc_start)
     s->gen_insn_data =
         tcg_malloc(sizeof(uint64_t) * s->gen_tb->icount * start_words);
 
+    tcg_out_tb_start(s);
+
     num_insns = -1;
     QTAILQ_FOREACH(op, &s->ops, link) {
         TCGOpcode opc = op->opc;
diff --git a/tcg/aarch64/tcg-target.c.inc b/tcg/aarch64/tcg-target.c.inc
index 35ca80cd56..8d71ac68f6 100644
--- a/tcg/aarch64/tcg-target.c.inc
+++ b/tcg/aarch64/tcg-target.c.inc
@@ -3123,6 +3123,11 @@ static void tcg_target_qemu_prologue(TCGContext *s)
     tcg_out_insn(s, 3207, RET, TCG_REG_LR);
 }
 
+static void tcg_out_tb_start(TCGContext *s)
+{
+    /* nothing to do */
+}
+
 static void tcg_out_nop_fill(tcg_insn_unit *p, int count)
 {
     int i;
diff --git a/tcg/arm/tcg-target.c.inc b/tcg/arm/tcg-target.c.inc
index 83e286088f..7473b23672 100644
--- a/tcg/arm/tcg-target.c.inc
+++ b/tcg/arm/tcg-target.c.inc
@@ -2951,6 +2951,11 @@ static void tcg_out_epilogue(TCGContext *s)
                   (1 << TCG_REG_R10) | (1 << TCG_REG_R11) | (1 << TCG_REG_PC));
 }
 
+static void tcg_out_tb_start(TCGContext *s)
+{
+    /* nothing to do */
+}
+
 typedef struct {
     DebugFrameHeader h;
     uint8_t fde_def_cfa[4];
diff --git a/tcg/i386/tcg-target.c.inc b/tcg/i386/tcg-target.c.inc
index a6b2eae995..05581dd89d 100644
--- a/tcg/i386/tcg-target.c.inc
+++ b/tcg/i386/tcg-target.c.inc
@@ -4114,6 +4114,11 @@ static void tcg_target_qemu_prologue(TCGContext *s)
     tcg_out_opc(s, OPC_RET, 0, 0, 0);
 }
 
+static void tcg_out_tb_start(TCGContext *s)
+{
+    /* nothing to do */
+}
+
 static void tcg_out_nop_fill(tcg_insn_unit *p, int count)
 {
     memset(p, 0x90, count);
diff --git a/tcg/loongarch64/tcg-target.c.inc b/tcg/loongarch64/tcg-target.c.inc
index baf5fc3819..29281e954b 100644
--- a/tcg/loongarch64/tcg-target.c.inc
+++ b/tcg/loongarch64/tcg-target.c.inc
@@ -1698,6 +1698,11 @@ static void tcg_target_qemu_prologue(TCGContext *s)
     tcg_out_opc_jirl(s, TCG_REG_ZERO, TCG_REG_RA, 0);
 }
 
+static void tcg_out_tb_start(TCGContext *s)
+{
+    /* nothing to do */
+}
+
 static void tcg_target_init(TCGContext *s)
 {
     unsigned long hwcap = qemu_getauxval(AT_HWCAP);
diff --git a/tcg/mips/tcg-target.c.inc b/tcg/mips/tcg-target.c.inc
index 9faa8bdf0b..b4da737dbb 100644
--- a/tcg/mips/tcg-target.c.inc
+++ b/tcg/mips/tcg-target.c.inc
@@ -2628,6 +2628,11 @@ static void tcg_target_qemu_prologue(TCGContext *s)
     tcg_out_opc_reg(s, OPC_OR, TCG_TMP3, TCG_TMP3, TCG_TMP1);
 }
 
+static void tcg_out_tb_start(TCGContext *s)
+{
+    /* nothing to do */
+}
+
 static void tcg_target_init(TCGContext *s)
 {
     tcg_target_detect_isa();
diff --git a/tcg/ppc/tcg-target.c.inc b/tcg/ppc/tcg-target.c.inc
index 642d0fd128..97b7697921 100644
--- a/tcg/ppc/tcg-target.c.inc
+++ b/tcg/ppc/tcg-target.c.inc
@@ -2482,6 +2482,11 @@ static void tcg_target_qemu_prologue(TCGContext *s)
     tcg_out32(s, BCLR | BO_ALWAYS);
 }
 
+static void tcg_out_tb_start(TCGContext *s)
+{
+    /* nothing to do */
+}
+
 static void tcg_out_exit_tb(TCGContext *s, uintptr_t arg)
 {
     tcg_out_movi(s, TCG_TYPE_PTR, TCG_REG_R3, arg);
diff --git a/tcg/riscv/tcg-target.c.inc b/tcg/riscv/tcg-target.c.inc
index eeaeb6b6e3..22834d087b 100644
--- a/tcg/riscv/tcg-target.c.inc
+++ b/tcg/riscv/tcg-target.c.inc
@@ -2054,6 +2054,11 @@ static void tcg_target_qemu_prologue(TCGContext *s)
     tcg_out_opc_imm(s, OPC_JALR, TCG_REG_ZERO, TCG_REG_RA, 0);
 }
 
+static void tcg_out_tb_start(TCGContext *s)
+{
+    /* nothing to do */
+}
+
 static volatile sig_atomic_t got_sigill;
 
 static void sigill_handler(int signo, siginfo_t *si, void *data)
diff --git a/tcg/s390x/tcg-target.c.inc b/tcg/s390x/tcg-target.c.inc
index a94f7908d6..379aaef1e5 100644
--- a/tcg/s390x/tcg-target.c.inc
+++ b/tcg/s390x/tcg-target.c.inc
@@ -3457,6 +3457,11 @@ static void tcg_target_qemu_prologue(TCGContext *s)
     tcg_out_insn(s, RR, BCR, S390_CC_ALWAYS, TCG_REG_R14);
 }
 
+static void tcg_out_tb_start(TCGContext *s)
+{
+    /* nothing to do */
+}
+
 static void tcg_out_nop_fill(tcg_insn_unit *p, int count)
 {
     memset(p, 0x07, count * sizeof(tcg_insn_unit));
diff --git a/tcg/sparc64/tcg-target.c.inc b/tcg/sparc64/tcg-target.c.inc
index ffcb879211..6458ca202d 100644
--- a/tcg/sparc64/tcg-target.c.inc
+++ b/tcg/sparc64/tcg-target.c.inc
@@ -955,6 +955,11 @@ static void tcg_target_qemu_prologue(TCGContext *s)
     tcg_out_movi_s13(s, TCG_REG_O0, 0);
 }
 
+static void tcg_out_tb_start(TCGContext *s)
+{
+    /* nothing to do */
+}
+
 static void tcg_out_nop_fill(tcg_insn_unit *p, int count)
 {
     int i;
diff --git a/tcg/tci/tcg-target.c.inc b/tcg/tci/tcg-target.c.inc
index 253f27f174..95b3352f82 100644
--- a/tcg/tci/tcg-target.c.inc
+++ b/tcg/tci/tcg-target.c.inc
@@ -955,6 +955,11 @@ static inline void tcg_target_qemu_prologue(TCGContext *s)
 {
 }
 
+static void tcg_out_tb_start(TCGContext *s)
+{
+    /* nothing to do */
+}
+
 bool tcg_target_has_memory_bswap(MemOp memop)
 {
     return true;
-- 
2.34.1

[PATCH v3 03/14] tcg/ppc: Enable direct branching tcg_out_goto_tb with TCG_REG_TB

[Richard Henderson]

From: Jordan Niethe <jniethe5@gmail.com>

Direct branch patching was disabled when using TCG_REG_TB in commit
736a1588c1 ("tcg/ppc: Fix race in goto_tb implementation").

The issue with direct branch patching with TCG_REG_TB is the lack of
synchronization between the new TCG_REG_TB being established and the
direct branch being patched in.

If each translation block is responsible for establishing its own
TCG_REG_TB then there can be no synchronization issue.

Make each translation block begin by setting up its own TCG_REG_TB.
Use the preferred 'bcl 20,31,$+4' sequence.

Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
[rth: Split out tcg_out_tb_start, power9 addpcis]
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 tcg/ppc/tcg-target.c.inc | 48 ++++++++++++++--------------------------
 1 file changed, 17 insertions(+), 31 deletions(-)

diff --git a/tcg/ppc/tcg-target.c.inc b/tcg/ppc/tcg-target.c.inc
index 97b7697921..134a9bbcb6 100644
--- a/tcg/ppc/tcg-target.c.inc
+++ b/tcg/ppc/tcg-target.c.inc
@@ -2464,9 +2464,6 @@ static void tcg_target_qemu_prologue(TCGContext *s)
 
     tcg_out_mov(s, TCG_TYPE_PTR, TCG_AREG0, tcg_target_call_iarg_regs[0]);
     tcg_out32(s, MTSPR | RS(tcg_target_call_iarg_regs[1]) | CTR);
-    if (USE_REG_TB) {
-        tcg_out_mov(s, TCG_TYPE_PTR, TCG_REG_TB, tcg_target_call_iarg_regs[1]);
-    }
     tcg_out32(s, BCCTR | BO_ALWAYS);
 
     /* Epilogue */
@@ -2484,7 +2481,13 @@ static void tcg_target_qemu_prologue(TCGContext *s)
 
 static void tcg_out_tb_start(TCGContext *s)
 {
-    /* nothing to do */
+    /* Load TCG_REG_TB. */
+    if (USE_REG_TB) {
+        /* bcl 20,31,$+4 (preferred form for getting nia) */
+        tcg_out32(s, BC | BO_ALWAYS | BI(7, CR_SO) | 0x4 | LK);
+        tcg_out32(s, MFSPR | RT(TCG_REG_TB) | LR);
+        tcg_out32(s, ADDI | TAI(TCG_REG_TB, TCG_REG_TB, -4));
+    }
 }
 
 static void tcg_out_exit_tb(TCGContext *s, uintptr_t arg)
@@ -2497,32 +2500,22 @@ static void tcg_out_goto_tb(TCGContext *s, int which)
 {
     uintptr_t ptr = get_jmp_target_addr(s, which);
 
+    /* Direct branch will be patched by tb_target_set_jmp_target. */
+    set_jmp_insn_offset(s, which);
+    tcg_out32(s, NOP);
+
+    /* When branch is out of range, fall through to indirect. */
     if (USE_REG_TB) {
         ptrdiff_t offset = tcg_tbrel_diff(s, (void *)ptr);
-        tcg_out_mem_long(s, LD, LDX, TCG_REG_TB, TCG_REG_TB, offset);
-    
-        /* TODO: Use direct branches when possible. */
-        set_jmp_insn_offset(s, which);
-        tcg_out32(s, MTSPR | RS(TCG_REG_TB) | CTR);
-
-        tcg_out32(s, BCCTR | BO_ALWAYS);
-
-        /* For the unlinked case, need to reset TCG_REG_TB.  */
-        set_jmp_reset_offset(s, which);
-        tcg_out_mem_long(s, ADDI, ADD, TCG_REG_TB, TCG_REG_TB,
-                         -tcg_current_code_size(s));
+        tcg_out_mem_long(s, LD, LDX, TCG_REG_TMP1, TCG_REG_TB, offset);
     } else {
-        /* Direct branch will be patched by tb_target_set_jmp_target. */
-        set_jmp_insn_offset(s, which);
-        tcg_out32(s, NOP);
-
-        /* When branch is out of range, fall through to indirect. */
         tcg_out_movi(s, TCG_TYPE_PTR, TCG_REG_TMP1, ptr - (int16_t)ptr);
         tcg_out_ld(s, TCG_TYPE_PTR, TCG_REG_TMP1, TCG_REG_TMP1, (int16_t)ptr);
-        tcg_out32(s, MTSPR | RS(TCG_REG_TMP1) | CTR);
-        tcg_out32(s, BCCTR | BO_ALWAYS);
-        set_jmp_reset_offset(s, which);
     }
+
+    tcg_out32(s, MTSPR | RS(TCG_REG_TMP1) | CTR);
+    tcg_out32(s, BCCTR | BO_ALWAYS);
+    set_jmp_reset_offset(s, which);
 }
 
 void tb_target_set_jmp_target(const TranslationBlock *tb, int n,
@@ -2532,10 +2525,6 @@ void tb_target_set_jmp_target(const TranslationBlock *tb, int n,
     intptr_t diff = addr - jmp_rx;
     tcg_insn_unit insn;
 
-    if (USE_REG_TB) {
-        return;
-    }
-
     if (in_range_b(diff)) {
         insn = B | (diff & 0x3fffffc);
     } else {
@@ -2555,9 +2544,6 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc,
     switch (opc) {
     case INDEX_op_goto_ptr:
         tcg_out32(s, MTSPR | RS(args[0]) | CTR);
-        if (USE_REG_TB) {
-            tcg_out_mov(s, TCG_TYPE_PTR, TCG_REG_TB, args[0]);
-        }
         tcg_out32(s, ADDI | TAI(TCG_REG_R3, 0, 0));
         tcg_out32(s, BCCTR | BO_ALWAYS);
         break;
-- 
2.34.1

[PATCH v3 04/14] tcg/ppc: Reinterpret tb-relative to TB+4

[Richard Henderson]

It saves one insn to load the address of TB+4 instead of TB.
Adjust all of the indexing to match.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 tcg/ppc/tcg-target.c.inc | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/tcg/ppc/tcg-target.c.inc b/tcg/ppc/tcg-target.c.inc
index 134a9bbcb6..19004fa568 100644
--- a/tcg/ppc/tcg-target.c.inc
+++ b/tcg/ppc/tcg-target.c.inc
@@ -215,6 +215,12 @@ static const int tcg_target_callee_save_regs[] = {
     TCG_REG_R31
 };
 
+/* For PPC, we use TB+4 instead of TB as the base. */
+static inline ptrdiff_t ppc_tbrel_diff(TCGContext *s, const void *target)
+{
+    return tcg_tbrel_diff(s, target) - 4;
+}
+
 static inline bool in_range_b(tcg_target_long target)
 {
     return target == sextract64(target, 0, 26);
@@ -986,7 +992,7 @@ static void tcg_out_movi_int(TCGContext *s, TCGType type, TCGReg ret,
     }
 
     /* Load addresses within the TB with one insn.  */
-    tb_diff = tcg_tbrel_diff(s, (void *)arg);
+    tb_diff = ppc_tbrel_diff(s, (void *)arg);
     if (!in_prologue && USE_REG_TB && tb_diff == (int16_t)tb_diff) {
         tcg_out32(s, ADDI | TAI(ret, TCG_REG_TB, tb_diff));
         return;
@@ -1039,7 +1045,7 @@ static void tcg_out_movi_int(TCGContext *s, TCGType type, TCGReg ret,
     /* Use the constant pool, if possible.  */
     if (!in_prologue && USE_REG_TB) {
         new_pool_label(s, arg, R_PPC_ADDR16, s->code_ptr,
-                       tcg_tbrel_diff(s, NULL));
+                       ppc_tbrel_diff(s, NULL));
         tcg_out32(s, LD | TAI(ret, TCG_REG_TB, 0));
         return;
     }
@@ -1099,7 +1105,7 @@ static void tcg_out_dupi_vec(TCGContext *s, TCGType type, unsigned vece,
      */
     if (USE_REG_TB) {
         rel = R_PPC_ADDR16;
-        add = tcg_tbrel_diff(s, NULL);
+        add = ppc_tbrel_diff(s, NULL);
     } else {
         rel = R_PPC_ADDR32;
         add = 0;
@@ -2486,7 +2492,6 @@ static void tcg_out_tb_start(TCGContext *s)
         /* bcl 20,31,$+4 (preferred form for getting nia) */
         tcg_out32(s, BC | BO_ALWAYS | BI(7, CR_SO) | 0x4 | LK);
         tcg_out32(s, MFSPR | RT(TCG_REG_TB) | LR);
-        tcg_out32(s, ADDI | TAI(TCG_REG_TB, TCG_REG_TB, -4));
     }
 }
 
@@ -2506,7 +2511,7 @@ static void tcg_out_goto_tb(TCGContext *s, int which)
 
     /* When branch is out of range, fall through to indirect. */
     if (USE_REG_TB) {
-        ptrdiff_t offset = tcg_tbrel_diff(s, (void *)ptr);
+        ptrdiff_t offset = ppc_tbrel_diff(s, (void *)ptr);
         tcg_out_mem_long(s, LD, LDX, TCG_REG_TMP1, TCG_REG_TB, offset);
     } else {
         tcg_out_movi(s, TCG_TYPE_PTR, TCG_REG_TMP1, ptr - (int16_t)ptr);
-- 
2.34.1

[PATCH v3 05/14] tcg/ppc: Use ADDPCIS in tcg_out_tb_start

[Richard Henderson]

With ISA v3.0, we can use ADDPCIS instead of BCL+MFLR to load NIP.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 tcg/ppc/tcg-target.c.inc | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/tcg/ppc/tcg-target.c.inc b/tcg/ppc/tcg-target.c.inc
index 19004fa568..36b4f61236 100644
--- a/tcg/ppc/tcg-target.c.inc
+++ b/tcg/ppc/tcg-target.c.inc
@@ -362,6 +362,7 @@ static bool tcg_target_const_match(int64_t val, TCGType type, int ct)
 #define CRNAND XO19(225)
 #define CROR   XO19(449)
 #define CRNOR  XO19( 33)
+#define ADDPCIS XO19( 2)
 
 #define EXTSB  XO31(954)
 #define EXTSH  XO31(922)
@@ -854,6 +855,19 @@ static inline void tcg_out_sari64(TCGContext *s, TCGReg dst, TCGReg src, int c)
     tcg_out32(s, SRADI | RA(dst) | RS(src) | SH(c & 0x1f) | ((c >> 4) & 2));
 }
 
+static void tcg_out_addpcis(TCGContext *s, TCGReg dst, intptr_t imm)
+{
+    int d0, d1, d2;
+
+    tcg_debug_assert((imm & 0xffff) == 0);
+    tcg_debug_assert(imm == (int32_t)imm);
+
+    d2 = imm & 1;
+    d1 = (imm >> 1) & 0x1f;
+    d0 = (imm >> 6) & 0x3ff;
+    tcg_out32(s, ADDPCIS | RT(dst) | (d1 << 16) | (d0 << 6) | d2);
+}
+
 static void tcg_out_bswap16(TCGContext *s, TCGReg dst, TCGReg src, int flags)
 {
     TCGReg tmp = dst == src ? TCG_REG_R0 : dst;
@@ -2489,9 +2503,14 @@ static void tcg_out_tb_start(TCGContext *s)
 {
     /* Load TCG_REG_TB. */
     if (USE_REG_TB) {
-        /* bcl 20,31,$+4 (preferred form for getting nia) */
-        tcg_out32(s, BC | BO_ALWAYS | BI(7, CR_SO) | 0x4 | LK);
-        tcg_out32(s, MFSPR | RT(TCG_REG_TB) | LR);
+        if (have_isa_3_00) {
+            /* lnia REG_TB */
+            tcg_out_addpcis(s, TCG_REG_TB, 0);
+        } else {
+            /* bcl 20,31,$+4 (preferred form for getting nia) */
+            tcg_out32(s, BC | BO_ALWAYS | BI(7, CR_SO) | 0x4 | LK);
+            tcg_out32(s, MFSPR | RT(TCG_REG_TB) | LR);
+        }
     }
 }
 
-- 
2.34.1

[PATCH v3 06/14] tcg/ppc: Use ADDPCIS in tcg_out_movi_int

[Richard Henderson]

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 tcg/ppc/tcg-target.c.inc | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/tcg/ppc/tcg-target.c.inc b/tcg/ppc/tcg-target.c.inc
index 36b4f61236..a302bfff2e 100644
--- a/tcg/ppc/tcg-target.c.inc
+++ b/tcg/ppc/tcg-target.c.inc
@@ -1050,6 +1050,19 @@ static void tcg_out_movi_int(TCGContext *s, TCGType type, TCGReg ret,
         return;
     }
 
+    /* Load addresses within 2GB with 2 insns. */
+    if (have_isa_3_00) {
+        intptr_t hi = tcg_pcrel_diff(s, (void *)arg) - 4;
+        int16_t lo = hi;
+
+        hi -= lo;
+        if (hi == (int32_t)hi) {
+            tcg_out_addpcis(s, TCG_REG_TMP2, hi);
+            tcg_out32(s, ADDI | TAI(ret, TCG_REG_TMP2, lo));
+            return;
+        }
+    }
+
     /* Load addresses within 2GB of TB with 2 (or rarely 3) insns.  */
     if (!in_prologue && USE_REG_TB && tb_diff == (int32_t)tb_diff) {
         tcg_out_mem_long(s, ADDI, ADD, ret, TCG_REG_TB, tb_diff);
-- 
2.34.1

[PATCH v3 07/14] tcg/ppc: Use ADDPCIS for the constant pool

[Richard Henderson]

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 tcg/ppc/tcg-target.c.inc | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/tcg/ppc/tcg-target.c.inc b/tcg/ppc/tcg-target.c.inc
index a302bfff2e..a5c1891eb6 100644
--- a/tcg/ppc/tcg-target.c.inc
+++ b/tcg/ppc/tcg-target.c.inc
@@ -1076,6 +1076,12 @@ static void tcg_out_movi_int(TCGContext *s, TCGType type, TCGReg ret,
         tcg_out32(s, LD | TAI(ret, TCG_REG_TB, 0));
         return;
     }
+    if (have_isa_3_00) {
+        tcg_out_addpcis(s, TCG_REG_TMP2, 0);
+        new_pool_label(s, arg, R_PPC_REL14, s->code_ptr, 0);
+        tcg_out32(s, LD | TAI(ret, TCG_REG_TMP2, 0));
+        return;
+    }
 
     tmp = arg >> 31 >> 1;
     tcg_out_movi(s, TCG_TYPE_I32, ret, tmp);
@@ -1133,6 +1139,10 @@ static void tcg_out_dupi_vec(TCGContext *s, TCGType type, unsigned vece,
     if (USE_REG_TB) {
         rel = R_PPC_ADDR16;
         add = ppc_tbrel_diff(s, NULL);
+    } else if (have_isa_3_00) {
+        tcg_out_addpcis(s, TCG_REG_TMP1, 0);
+        rel = R_PPC_REL14;
+        add = 0;
     } else {
         rel = R_PPC_ADDR32;
         add = 0;
@@ -1159,6 +1169,8 @@ static void tcg_out_dupi_vec(TCGContext *s, TCGType type, unsigned vece,
     if (USE_REG_TB) {
         tcg_out32(s, ADDI | TAI(TCG_REG_TMP1, 0, 0));
         load_insn |= RA(TCG_REG_TB);
+    } else if (have_isa_3_00) {
+        tcg_out32(s, ADDI | TAI(TCG_REG_TMP1, TCG_REG_TMP1, 0));
     } else {
         tcg_out32(s, ADDIS | TAI(TCG_REG_TMP1, 0, 0));
         tcg_out32(s, ADDI | TAI(TCG_REG_TMP1, TCG_REG_TMP1, 0));
-- 
2.34.1

[PATCH v3 08/14] tcg/ppc: Use ADDPCIS in tcg_out_goto_tb

[Richard Henderson]

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 tcg/ppc/tcg-target.c.inc | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/tcg/ppc/tcg-target.c.inc b/tcg/ppc/tcg-target.c.inc
index a5c1891eb6..b7d1b4f1bb 100644
--- a/tcg/ppc/tcg-target.c.inc
+++ b/tcg/ppc/tcg-target.c.inc
@@ -2548,6 +2548,7 @@ static void tcg_out_exit_tb(TCGContext *s, uintptr_t arg)
 static void tcg_out_goto_tb(TCGContext *s, int which)
 {
     uintptr_t ptr = get_jmp_target_addr(s, which);
+    int16_t lo;
 
     /* Direct branch will be patched by tb_target_set_jmp_target. */
     set_jmp_insn_offset(s, which);
@@ -2557,9 +2558,15 @@ static void tcg_out_goto_tb(TCGContext *s, int which)
     if (USE_REG_TB) {
         ptrdiff_t offset = ppc_tbrel_diff(s, (void *)ptr);
         tcg_out_mem_long(s, LD, LDX, TCG_REG_TMP1, TCG_REG_TB, offset);
+    } else if (have_isa_3_00) {
+        ptrdiff_t offset = tcg_pcrel_diff(s, (void *)ptr) - 4;
+        lo = offset;
+        tcg_out_addpcis(s, TCG_REG_TMP1, offset - lo);
+        tcg_out_ld(s, TCG_TYPE_PTR, TCG_REG_TMP1, TCG_REG_TMP1, lo);
     } else {
-        tcg_out_movi(s, TCG_TYPE_PTR, TCG_REG_TMP1, ptr - (int16_t)ptr);
-        tcg_out_ld(s, TCG_TYPE_PTR, TCG_REG_TMP1, TCG_REG_TMP1, (int16_t)ptr);
+        lo = ptr;
+        tcg_out_movi(s, TCG_TYPE_PTR, TCG_REG_TMP1, ptr - lo);
+        tcg_out_ld(s, TCG_TYPE_PTR, TCG_REG_TMP1, TCG_REG_TMP1, lo);
     }
 
     tcg_out32(s, MTSPR | RS(TCG_REG_TMP1) | CTR);
-- 
2.34.1

[PATCH v3 09/14] tcg/ppc: Use PADDI in tcg_out_movi

[Richard Henderson]

PADDI can load 34-bit immediates and 34-bit pc-relative addresses.

Reviewed-by: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 tcg/ppc/tcg-target.c.inc | 51 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)

diff --git a/tcg/ppc/tcg-target.c.inc b/tcg/ppc/tcg-target.c.inc
index b7d1b4f1bb..40472f3d00 100644
--- a/tcg/ppc/tcg-target.c.inc
+++ b/tcg/ppc/tcg-target.c.inc
@@ -714,6 +714,38 @@ static bool patch_reloc(tcg_insn_unit *code_ptr, int type,
     return true;
 }
 
+/* Ensure that the prefixed instruction does not cross a 64-byte boundary. */
+static bool tcg_out_need_prefix_align(TCGContext *s)
+{
+    return ((uintptr_t)s->code_ptr & 0x3f) == 0x3c;
+}
+
+static void tcg_out_prefix_align(TCGContext *s)
+{
+    if (tcg_out_need_prefix_align(s)) {
+        tcg_out32(s, NOP);
+    }
+}
+
+static ptrdiff_t tcg_pcrel_diff_for_prefix(TCGContext *s, const void *target)
+{
+    return tcg_pcrel_diff(s, target) - (tcg_out_need_prefix_align(s) ? 4 : 0);
+}
+
+/* Output Type 10 Prefix - Modified Load/Store Form (MLS:D) */
+static void tcg_out_mls_d(TCGContext *s, tcg_insn_unit opc, unsigned rt,
+                          unsigned ra, tcg_target_long imm, bool r)
+{
+    tcg_insn_unit p, i;
+
+    p = OPCD(1) | (2 << 24) | (r << 20) | ((imm >> 16) & 0x3ffff);
+    i = opc | TAI(rt, ra, imm);
+
+    tcg_out_prefix_align(s);
+    tcg_out32(s, p);
+    tcg_out32(s, i);
+}
+
 static void tcg_out_mem_long(TCGContext *s, int opi, int opx, TCGReg rt,
                              TCGReg base, tcg_target_long offset);
 
@@ -1012,6 +1044,25 @@ static void tcg_out_movi_int(TCGContext *s, TCGType type, TCGReg ret,
         return;
     }
 
+    /*
+     * Load values up to 34 bits, and pc-relative addresses,
+     * with one prefixed insn.
+     */
+    if (have_isa_3_10) {
+        if (arg == sextract64(arg, 0, 34)) {
+            /* pli ret,value = paddi ret,0,value,0 */
+            tcg_out_mls_d(s, ADDI, ret, 0, arg, 0);
+            return;
+        }
+
+        tmp = tcg_pcrel_diff_for_prefix(s, (void *)arg);
+        if (tmp == sextract64(tmp, 0, 34)) {
+            /* pla ret,value = paddi ret,0,value,1 */
+            tcg_out_mls_d(s, ADDI, ret, 0, tmp, 1);
+            return;
+        }
+    }
+
     /* Load 32-bit immediates with two insns.  Note that we've already
        eliminated bare ADDIS, so we know both insns are required.  */
     if (TCG_TARGET_REG_BITS == 32 || arg == (int32_t)arg) {
-- 
2.34.1

[PATCH v3 10/14] tcg/ppc: Use prefixed instructions in tcg_out_mem_long

[Richard Henderson]

When the offset is out of range of the non-prefixed insn, but
fits the 34-bit immediate of the prefixed insn, use that.

Reviewed-by: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 tcg/ppc/tcg-target.c.inc | 66 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)

diff --git a/tcg/ppc/tcg-target.c.inc b/tcg/ppc/tcg-target.c.inc
index 40472f3d00..1aece2cbf7 100644
--- a/tcg/ppc/tcg-target.c.inc
+++ b/tcg/ppc/tcg-target.c.inc
@@ -329,6 +329,15 @@ static bool tcg_target_const_match(int64_t val, TCGType type, int ct)
 #define STDX   XO31(149)
 #define STQ    XO62(  2)
 
+#define PLWA   OPCD( 41)
+#define PLD    OPCD( 57)
+#define PLXSD  OPCD( 42)
+#define PLXV   OPCD(25 * 2 + 1)  /* force tx=1 */
+
+#define PSTD   OPCD( 61)
+#define PSTXSD OPCD( 46)
+#define PSTXV  OPCD(27 * 2 + 1)  /* force sx=1 */
+
 #define ADDIC  OPCD( 12)
 #define ADDI   OPCD( 14)
 #define ADDIS  OPCD( 15)
@@ -732,6 +741,20 @@ static ptrdiff_t tcg_pcrel_diff_for_prefix(TCGContext *s, const void *target)
     return tcg_pcrel_diff(s, target) - (tcg_out_need_prefix_align(s) ? 4 : 0);
 }
 
+/* Output Type 00 Prefix - 8-Byte Load/Store Form (8LS:D) */
+static void tcg_out_8ls_d(TCGContext *s, tcg_insn_unit opc, unsigned rt,
+                          unsigned ra, tcg_target_long imm, bool r)
+{
+    tcg_insn_unit p, i;
+
+    p = OPCD(1) | (r << 20) | ((imm >> 16) & 0x3ffff);
+    i = opc | TAI(rt, ra, imm);
+
+    tcg_out_prefix_align(s);
+    tcg_out32(s, p);
+    tcg_out32(s, i);
+}
+
 /* Output Type 10 Prefix - Modified Load/Store Form (MLS:D) */
 static void tcg_out_mls_d(TCGContext *s, tcg_insn_unit opc, unsigned rt,
                           unsigned ra, tcg_target_long imm, bool r)
@@ -1413,6 +1436,49 @@ static void tcg_out_mem_long(TCGContext *s, int opi, int opx, TCGReg rt,
         break;
     }
 
+    /* For unaligned or large offsets, use the prefixed form. */
+    if (have_isa_3_10
+        && (offset != (int16_t)offset || (offset & align))
+        && offset == sextract64(offset, 0, 34)) {
+        /*
+         * Note that the MLS:D insns retain their un-prefixed opcode,
+         * while the 8LS:D insns use a different opcode space.
+         */
+        switch (opi) {
+        case LBZ:
+        case LHZ:
+        case LHA:
+        case LWZ:
+        case STB:
+        case STH:
+        case STW:
+        case ADDI:
+            tcg_out_mls_d(s, opi, rt, base, offset, 0);
+            return;
+        case LWA:
+            tcg_out_8ls_d(s, PLWA, rt, base, offset, 0);
+            return;
+        case LD:
+            tcg_out_8ls_d(s, PLD, rt, base, offset, 0);
+            return;
+        case STD:
+            tcg_out_8ls_d(s, PSTD, rt, base, offset, 0);
+            return;
+        case LXSD:
+            tcg_out_8ls_d(s, PLXSD, rt & 31, base, offset, 0);
+            return;
+        case STXSD:
+            tcg_out_8ls_d(s, PSTXSD, rt & 31, base, offset, 0);
+            return;
+        case LXV:
+            tcg_out_8ls_d(s, PLXV, rt & 31, base, offset, 0);
+            return;
+        case STXV:
+            tcg_out_8ls_d(s, PSTXV, rt & 31, base, offset, 0);
+            return;
+        }
+    }
+
     /* For unaligned, or very large offsets, use the indexed form.  */
     if (offset & align || offset != (int32_t)offset || opi == 0) {
         if (rs == base) {
-- 
2.34.1

[PATCH v3 11/14] tcg/ppc: Use PLD in tcg_out_movi for constant pool

[Richard Henderson]

The prefixed instruction has a pc-relative form to use here.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 tcg/ppc/tcg-target.c.inc | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/tcg/ppc/tcg-target.c.inc b/tcg/ppc/tcg-target.c.inc
index 1aece2cbf7..670811b636 100644
--- a/tcg/ppc/tcg-target.c.inc
+++ b/tcg/ppc/tcg-target.c.inc
@@ -101,6 +101,10 @@
 #define ALL_GENERAL_REGS  0xffffffffu
 #define ALL_VECTOR_REGS   0xffffffff00000000ull
 
+#ifndef R_PPC64_PCREL34
+#define R_PPC64_PCREL34  132
+#endif
+
 #define have_isel  (cpuinfo & CPUINFO_ISEL)
 
 #ifndef CONFIG_SOFTMMU
@@ -266,6 +270,19 @@ static bool reloc_pc14(tcg_insn_unit *src_rw, const tcg_insn_unit *target)
     return false;
 }
 
+static bool reloc_pc34(tcg_insn_unit *src_rw, const tcg_insn_unit *target)
+{
+    const tcg_insn_unit *src_rx = tcg_splitwx_to_rx(src_rw);
+    ptrdiff_t disp = tcg_ptr_byte_diff(target, src_rx);
+
+    if (disp == sextract64(disp, 0, 34)) {
+        src_rw[0] = (src_rw[0] & ~0x3ffff) | ((disp >> 16) & 0x3ffff);
+        src_rw[1] = (src_rw[1] & ~0xffff) | (disp & 0xffff);
+        return true;
+    }
+    return false;
+}
+
 /* test if a constant matches the constraint */
 static bool tcg_target_const_match(int64_t val, TCGType type, int ct)
 {
@@ -691,6 +708,8 @@ static bool patch_reloc(tcg_insn_unit *code_ptr, int type,
         return reloc_pc14(code_ptr, target);
     case R_PPC_REL24:
         return reloc_pc24(code_ptr, target);
+    case R_PPC64_PCREL34:
+        return reloc_pc34(code_ptr, target);
     case R_PPC_ADDR16:
         /*
          * We are (slightly) abusing this relocation type.  In particular,
@@ -1150,6 +1169,11 @@ static void tcg_out_movi_int(TCGContext *s, TCGType type, TCGReg ret,
         tcg_out32(s, LD | TAI(ret, TCG_REG_TB, 0));
         return;
     }
+    if (have_isa_3_10) {
+        tcg_out_8ls_d(s, PLD, ret, 0, 0, 1);
+        new_pool_label(s, arg, R_PPC64_PCREL34, s->code_ptr - 2, 0);
+        return;
+    }
     if (have_isa_3_00) {
         tcg_out_addpcis(s, TCG_REG_TMP2, 0);
         new_pool_label(s, arg, R_PPC_REL14, s->code_ptr, 0);
-- 
2.34.1

[PATCH v3 12/14] tcg/ppc: Use prefixed instructions in tcg_out_dupi_vec

[Richard Henderson]

The prefixed instructions have a pc-relative form to use here.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 tcg/ppc/tcg-target.c.inc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/tcg/ppc/tcg-target.c.inc b/tcg/ppc/tcg-target.c.inc
index 670811b636..0cdb7ef37a 100644
--- a/tcg/ppc/tcg-target.c.inc
+++ b/tcg/ppc/tcg-target.c.inc
@@ -1237,6 +1237,15 @@ static void tcg_out_dupi_vec(TCGContext *s, TCGType type, unsigned vece,
     if (USE_REG_TB) {
         rel = R_PPC_ADDR16;
         add = ppc_tbrel_diff(s, NULL);
+    } else if (have_isa_3_10) {
+        if (type == TCG_TYPE_V64) {
+            tcg_out_8ls_d(s, PLXSD, ret & 31, 0, 0, 1);
+            new_pool_label(s, val, R_PPC64_PCREL34, s->code_ptr - 2, 0);
+        } else {
+            tcg_out_8ls_d(s, PLXV, ret & 31, 0, 0, 1);
+            new_pool_l2(s, R_PPC64_PCREL34, s->code_ptr - 2, 0, val, val);
+        }
+        return;
     } else if (have_isa_3_00) {
         tcg_out_addpcis(s, TCG_REG_TMP1, 0);
         rel = R_PPC_REL14;
-- 
2.34.1

[PATCH v3 13/14] tcg/ppc: Use PLD in tcg_out_goto_tb

[Richard Henderson]

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 tcg/ppc/tcg-target.c.inc | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tcg/ppc/tcg-target.c.inc b/tcg/ppc/tcg-target.c.inc
index 0cdb7ef37a..20aaa90af2 100644
--- a/tcg/ppc/tcg-target.c.inc
+++ b/tcg/ppc/tcg-target.c.inc
@@ -2708,6 +2708,9 @@ static void tcg_out_goto_tb(TCGContext *s, int which)
     if (USE_REG_TB) {
         ptrdiff_t offset = ppc_tbrel_diff(s, (void *)ptr);
         tcg_out_mem_long(s, LD, LDX, TCG_REG_TMP1, TCG_REG_TB, offset);
+    } else if (have_isa_3_10) {
+        ptrdiff_t offset = tcg_pcrel_diff_for_prefix(s, (void *)ptr);
+        tcg_out_8ls_d(s, PLD, TCG_REG_TMP1, 0, offset, 1);
     } else if (have_isa_3_00) {
         ptrdiff_t offset = tcg_pcrel_diff(s, (void *)ptr) - 4;
         lo = offset;
-- 
2.34.1

[PATCH v3 14/14] RFC tcg/ppc: Disable TCG_REG_TB for Power9/Power10

[Richard Henderson]

This may or may not improve performance.
It appears to result in slightly larger code,
but perhaps not enough to matter.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 tcg/ppc/tcg-target.c.inc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tcg/ppc/tcg-target.c.inc b/tcg/ppc/tcg-target.c.inc
index 20aaa90af2..c1e0efb498 100644
--- a/tcg/ppc/tcg-target.c.inc
+++ b/tcg/ppc/tcg-target.c.inc
@@ -83,7 +83,7 @@
 #define TCG_VEC_TMP2    TCG_REG_V1
 
 #define TCG_REG_TB     TCG_REG_R31
-#define USE_REG_TB     (TCG_TARGET_REG_BITS == 64)
+#define USE_REG_TB     (TCG_TARGET_REG_BITS == 64 && !have_isa_3_00)
 
 /* Shorthand for size of a pointer.  Avoid promotion to unsigned.  */
 #define SZP  ((int)sizeof(void *))
-- 
2.34.1

Re: [PATCH v3 05/14] tcg/ppc: Use ADDPCIS in tcg_out_tb_start

[Jordan Niethe]

[-- Attachment #1: Type: text/plain, Size: 2255 bytes --]

On Wed, 16 Aug 2023, 5:57 am Richard Henderson, <
richard.henderson@linaro.org> wrote:

> With ISA v3.0, we can use ADDPCIS instead of BCL+MFLR to load NIP.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  tcg/ppc/tcg-target.c.inc | 25 ++++++++++++++++++++++---
>  1 file changed, 22 insertions(+), 3 deletions(-)
>
> diff --git a/tcg/ppc/tcg-target.c.inc b/tcg/ppc/tcg-target.c.inc
> index 19004fa568..36b4f61236 100644
> --- a/tcg/ppc/tcg-target.c.inc
> +++ b/tcg/ppc/tcg-target.c.inc
> @@ -362,6 +362,7 @@ static bool tcg_target_const_match(int64_t val,
> TCGType type, int ct)
>  #define CRNAND XO19(225)
>  #define CROR   XO19(449)
>  #define CRNOR  XO19( 33)
> +#define ADDPCIS XO19( 2)
>
>  #define EXTSB  XO31(954)
>  #define EXTSH  XO31(922)
> @@ -854,6 +855,19 @@ static inline void tcg_out_sari64(TCGContext *s,
> TCGReg dst, TCGReg src, int c)
>      tcg_out32(s, SRADI | RA(dst) | RS(src) | SH(c & 0x1f) | ((c >> 4) &
> 2));
>  }
>
> +static void tcg_out_addpcis(TCGContext *s, TCGReg dst, intptr_t imm)
> +{
> +    int d0, d1, d2;
> +
> +    tcg_debug_assert((imm & 0xffff) == 0);
> +    tcg_debug_assert(imm == (int32_t)imm);
> +
>

I think you need imm >>= 16 here.
Without that the next patch in the series crashes.

+    d2 = imm & 1;
> +    d1 = (imm >> 1) & 0x1f;
> +    d0 = (imm >> 6) & 0x3ff;
> +    tcg_out32(s, ADDPCIS | RT(dst) | (d1 << 16) | (d0 << 6) | d2);
> +}
> +
>  static void tcg_out_bswap16(TCGContext *s, TCGReg dst, TCGReg src, int
> flags)
>  {
>      TCGReg tmp = dst == src ? TCG_REG_R0 : dst;
> @@ -2489,9 +2503,14 @@ static void tcg_out_tb_start(TCGContext *s)
>  {
>      /* Load TCG_REG_TB. */
>      if (USE_REG_TB) {
> -        /* bcl 20,31,$+4 (preferred form for getting nia) */
> -        tcg_out32(s, BC | BO_ALWAYS | BI(7, CR_SO) | 0x4 | LK);
> -        tcg_out32(s, MFSPR | RT(TCG_REG_TB) | LR);
> +        if (have_isa_3_00) {
> +            /* lnia REG_TB */
> +            tcg_out_addpcis(s, TCG_REG_TB, 0);
> +        } else {
> +            /* bcl 20,31,$+4 (preferred form for getting nia) */
> +            tcg_out32(s, BC | BO_ALWAYS | BI(7, CR_SO) | 0x4 | LK);
> +            tcg_out32(s, MFSPR | RT(TCG_REG_TB) | LR);
> +        }
>      }
>  }
>
> --
> 2.34.1
>
>

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Re: [PATCH v3 05/14] tcg/ppc: Use ADDPCIS in tcg_out_tb_start

[Richard Henderson]

On 8/23/23 02:39, Jordan Niethe wrote:
>     +static void tcg_out_addpcis(TCGContext *s, TCGReg dst, intptr_t imm)
>     +{
>     +    int d0, d1, d2;
>     +
>     +    tcg_debug_assert((imm & 0xffff) == 0);
>     +    tcg_debug_assert(imm == (int32_t)imm);
>     +
> 
> 
> I think you need imm >>= 16 here.
> Without that the next patch in the series crashes.
> 
>     +    d2 = imm & 1;
>     +    d1 = (imm >> 1) & 0x1f;
>     +    d0 = (imm >> 6) & 0x3ff;

Yes indeed.  Silly error.  I wonder what went wrong in my testing...


r~

Re: [PATCH v3 14/14] RFC tcg/ppc: Disable TCG_REG_TB for Power9/Power10

[Jordan Niethe]

On Wed, Aug 16, 2023 at 5:57 AM Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> This may or may not improve performance.
> It appears to result in slightly larger code,
> but perhaps not enough to matter.

I have collected some power9 macro performance data for an smp compile workload:

Setup
-----

- Power9 powernv host
- mttcg smp 8 guest

Method
------

- Warm up compile skiboot (https://github.com/open-power/skiboot)
- Average time taken for 5 trials compiling skiboot with -j `nproc`

Results
-------


|                Patch                | Mean time (s) | stdev | Decrease (%) |
|-------------------------------------|---------------|-------|--------------|
| tcg: Add tcg_out_tb_start...        |        161.77 |  2.39 |            - |
| tcg/ppc: Enable direct branching... |        145.81 |  1.71 |          9.9 |
| tcg/ppc: Use ADDPCIS...             |        146.44 |  1.28 |          9.5 |
| RFC tcg/ppc: Disable TCG_REG_TB...  |        145.95 |  1.07 |          9.7 |


- Enabling direct branching is a performance gain, beyond that less conclusive.
- Using pcaddis for direct branching seems slightly better than bl +4
sequence for ISA v3.0.
- PC relative addressing seems slightly better than TOC relative addressing.

Any other suggestions for performance comparison?
I still have to try on a Power10.

>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  tcg/ppc/tcg-target.c.inc | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tcg/ppc/tcg-target.c.inc b/tcg/ppc/tcg-target.c.inc
> index 20aaa90af2..c1e0efb498 100644
> --- a/tcg/ppc/tcg-target.c.inc
> +++ b/tcg/ppc/tcg-target.c.inc
> @@ -83,7 +83,7 @@
>  #define TCG_VEC_TMP2    TCG_REG_V1
>
>  #define TCG_REG_TB     TCG_REG_R31
> -#define USE_REG_TB     (TCG_TARGET_REG_BITS == 64)
> +#define USE_REG_TB     (TCG_TARGET_REG_BITS == 64 && !have_isa_3_00)
>
>  /* Shorthand for size of a pointer.  Avoid promotion to unsigned.  */
>  #define SZP  ((int)sizeof(void *))
> --
> 2.34.1
>