[PATCH v2 1/2] alpha: pass -Wa,-mev6 only when using GNU as

[Matt Turner <mattst88@gmail.com>]

That flag exists to stop gas emulating instructions the assembler thinks
the target lacks.  It is a gas-only option, and LLVM's integrated
assembler does not emulate instructions in the first place, so nothing
is needed there.

Condition it on CONFIG_AS_IS_GNU rather than the compiler, so it is
still passed for clang builds using GNU as (LLVM_IAS=0) and omitted only
for the integrated assembler.

Signed-off-by: Matt Turner <mattst88@gmail.com>
---
Only this patch changed; patch 2/2 ("alpha: read $gp and $sp explicitly
for clang") is unchanged from v1 and is not resent.

Changes in v2:
- Drop the scripts/Makefile.clang CLANG_TARGET_FLAGS_alpha entry.  It
  will be sent separately when the alpha backend is upstreamed to LLVM.
- Condition -Wa,-mev6 on CONFIG_AS_IS_GNU rather than CONFIG_CC_IS_GCC,
  so it is still passed for clang builds using GNU as (LLVM_IAS=0).
- Reword the subject and commit message for the reduced scope.
- Link to v1: https://lore.kernel.org/r/20260803-alpha-clang-v1-0-1c4ba5ba7a64@gmail.com

 arch/alpha/Makefile | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/alpha/Makefile b/arch/alpha/Makefile
index 35445ff2e489..7074602dca94 100644
--- a/arch/alpha/Makefile
+++ b/arch/alpha/Makefile
@@ -27,10 +27,16 @@ cpuflags-$(CONFIG_ALPHA_GENERIC)	:= -mcpu=ev56 -mtune=ev6
 cflags-y				+= $(cpuflags-y)
 
 
+KBUILD_CFLAGS += $(cflags-y)
+
 # For TSUNAMI, we must have the assembler not emulate our instructions.
 # The same is true for IRONGATE, POLARIS, PYXIS.
 # BWX is most important, but we don't really want any emulation ever.
-KBUILD_CFLAGS += $(cflags-y) -Wa,-mev6
+# Only gas emulates instructions the target does not implement, and only gas
+# understands -mev6.  LLVM's integrated assembler never emulates.
+ifdef CONFIG_AS_IS_GNU
+KBUILD_CFLAGS += -Wa,-mev6
+endif
 
 libs-y				+= arch/alpha/lib/
 
-- 
2.54.0