A sign-extension has no effect on the result of a comparison
with 0 or with 1 when the original size is bigger than 1.
Optimize away the extension.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx>
---
simplify.c | 4 ++++
validation/optim/bool-sext-test.c | 1 -
2 files changed, 4 insertions(+), 1 deletion(-)
diff --git a/simplify.c b/simplify.c
index fb4bb3429..db2fba7ff 100644
--- a/simplify.c
+++ b/simplify.c
@@ -607,6 +607,10 @@ static int simplify_seteq_setne(struct instruction *insn, long long value)
remove_usage(old, &insn->src1);
return REPEAT_CSE;
+ case OP_SEXT:
+ if (value && (def->orig_type->bit_size == 1))
+ break;
+ /* Fall through */
case OP_ZEXT:
// Convert:
// *ext.m %s <- (1) %a
diff --git a/validation/optim/bool-sext-test.c b/validation/optim/bool-sext-test.c
index 0ca3dea9a..bd85e06ee 100644
--- a/validation/optim/bool-sext-test.c
+++ b/validation/optim/bool-sext-test.c
@@ -6,7 +6,6 @@ _Bool nes1( signed char a) { return a != 1; }
/*
* check-name: bool-sext-test
* check-command: test-linearize -Wno-decl $file
- * check-known-to-fail
*
* check-output-ignore
* check-output-excludes: sext\\.
--
2.18.0
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