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* [PATCH] fix usage in simplify_seteq_setne()
@ 2017-02-24  6:54 Luc Van Oostenryck
  0 siblings, 0 replies; only message in thread
From: Luc Van Oostenryck @ 2017-02-24  6:54 UTC (permalink / raw)
  To: linux-sparse; +Cc: Christopher Li, Luc Van Oostenryck

The usage was removed before the new operands were used
which can lead to undefined pseudos.

Fix this by moving the call to remove_usage() where
it should always have been: after the call to use_pseudo().

Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
---
 simplify.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/simplify.c b/simplify.c
index 3bc9985e8..76a599e50 100644
--- a/simplify.c
+++ b/simplify.c
@@ -432,7 +432,8 @@ static int compare_opcode(int opcode, int inverse)
 
 static int simplify_seteq_setne(struct instruction *insn, long long value)
 {
-	struct instruction *def = insn->src1->def;
+	pseudo_t old = insn->src1;
+	struct instruction *def = old->def;
 	pseudo_t src1, src2;
 	int inverse;
 	int opcode;
@@ -456,10 +457,10 @@ static int simplify_seteq_setne(struct instruction *insn, long long value)
 		// and similar for setne/eq ... 0/1
 		src1 = def->src1;
 		src2 = def->src2;
-		remove_usage(insn->src1, &insn->src1);
 		insn->opcode = compare_opcode(opcode, inverse);
 		use_pseudo(insn, src1, &insn->src1);
 		use_pseudo(insn, src2, &insn->src2);
+		remove_usage(old, &insn->src1);
 		return REPEAT_CSE;
 
 	default:
-- 
2.11.1


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2017-02-24  6:54 [PATCH] fix usage in simplify_seteq_setne() Luc Van Oostenryck

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