From cc21c4aa984c45aed1efcbcdc29c99124c89771e Mon Sep 17 00:00:00 2001 From: Tobias Grosser Date: Sun, 9 Jan 2011 16:00:11 +0000 Subject: Instcombine: Fix pattern where the sext did not dominate the icmp using it llvm-svn: 123121 --- llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'llvm/lib') diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp index 71a286ef69c..ff41ab834b1 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp @@ -281,8 +281,8 @@ Instruction *InstCombiner::visitSelectInstWithICmp(SelectInst &SI, Value *FalseVal = SI.getFalseValue(); // Check cases where the comparison is with a constant that - // can be adjusted to fit the min/max idiom. We may edit ICI in - // place here, so make sure the select is the only user. + // can be adjusted to fit the min/max idiom. We may move or edit ICI + // here, so make sure the select is the only user. if (ICI->hasOneUse()) if (ConstantInt *CI = dyn_cast(CmpRHS)) { // X < MIN ? T : F --> F @@ -364,6 +364,11 @@ Instruction *InstCombiner::visitSelectInstWithICmp(SelectInst &SI, ICI->setOperand(1, CmpRHS); SI.setOperand(1, TrueVal); SI.setOperand(2, FalseVal); + + // Move ICI instruction right before the select instruction. Otherwise + // the sext/zext value may be defined after the ICI instruction uses it. + ICI->moveBefore(&SI); + Changed = true; break; } -- cgit v1.2.3