From 42ef669d815fd9745cbd0c06e573052647cd16b3 Mon Sep 17 00:00:00 2001 From: Dan Gohman Date: Sat, 21 Aug 2010 02:32:36 +0000 Subject: Fix x86 fast-isel's cmp+branch folding to avoid folding when the comparison is in a different basic block from the branch. In such cases, the comparison's operands may not have initialized virtual registers available. llvm-svn: 111709 --- llvm/lib/Target/X86/X86FastISel.cpp | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'llvm/lib') diff --git a/llvm/lib/Target/X86/X86FastISel.cpp b/llvm/lib/Target/X86/X86FastISel.cpp index b7341f93eed..0c70eec4827 100644 --- a/llvm/lib/Target/X86/X86FastISel.cpp +++ b/llvm/lib/Target/X86/X86FastISel.cpp @@ -960,9 +960,11 @@ bool X86FastISel::X86SelectBranch(const Instruction *I) { MachineBasicBlock *TrueMBB = FuncInfo.MBBMap[BI->getSuccessor(0)]; MachineBasicBlock *FalseMBB = FuncInfo.MBBMap[BI->getSuccessor(1)]; - // Fold the common case of a conditional branch with a comparison. + // Fold the common case of a conditional branch with a comparison + // in the same block (values defined on other blocks may not have + // initialized registers). if (const CmpInst *CI = dyn_cast(BI->getCondition())) { - if (CI->hasOneUse()) { + if (CI->hasOneUse() && CI->getParent() == I->getParent()) { EVT VT = TLI.getValueType(CI->getOperand(0)->getType()); // Try to take advantage of fallthrough opportunities. -- cgit v1.2.3