Author: lattner
Date: Sun Jan 13 14:59:02 2008
New Revision: 45937
URL: http://llvm.org/viewvc/llvm-project?rev=45937&view=rev
Log:
Fix PR1907, a nasty miscompilation because instcombine didn't
realize that ne & sgt was a signed comparison (it was only
looking at whether the left compare was signed).
Added:
llvm/trunk/test/Transforms/InstCombine/2008-01-13-AndCmpCmp.ll
Modified:
llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp
Modified: llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp?rev=45937&r1=45936&r2=45937&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp Sun Jan 13
14:59:02 2008
@@ -3495,8 +3495,14 @@
ICmpInst::isSignedPredicate(LHSCC) ==
ICmpInst::isSignedPredicate(RHSCC))) {
// Ensure that the larger constant is on the RHS.
- ICmpInst::Predicate GT = ICmpInst::isSignedPredicate(LHSCC) ?
- ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
+ ICmpInst::Predicate GT;
+ if (ICmpInst::isSignedPredicate(LHSCC) ||
+ (ICmpInst::isEquality(LHSCC) &&
+ ICmpInst::isSignedPredicate(RHSCC)))
+ GT = ICmpInst::ICMP_SGT;
+ else
+ GT = ICmpInst::ICMP_UGT;
+
Constant *Cmp = ConstantExpr::getICmp(GT, LHSCst, RHSCst);
ICmpInst *LHS = cast<ICmpInst>(Op0);
if (cast<ConstantInt>(Cmp)->getZExtValue()) {
Added: llvm/trunk/test/Transforms/InstCombine/2008-01-13-AndCmpCmp.ll
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/2008-01-13-AndCmpCmp.ll?rev=45937&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/2008-01-13-AndCmpCmp.ll (added)
+++ llvm/trunk/test/Transforms/InstCombine/2008-01-13-AndCmpCmp.ll Sun Jan 13
14:59:02 2008
@@ -0,0 +1,9 @@
+; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep and
+; PR1907
+
+define i1 @test(i32 %c84.17) {
+ %tmp2696 = icmp ne i32 %c84.17, 34 ; <i1> [#uses=2]
+ %tmp2699 = icmp sgt i32 %c84.17, -1 ; <i1> [#uses=1]
+ %tmp2703 = and i1 %tmp2696, %tmp2699 ; <i1> [#uses=1]
+ ret i1 %tmp2703
+}
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