From 90b0d5cdd86d7436a92aac43e69b68be8c749dc9 Mon Sep 17 00:00:00 2001 From: Bob Wilson Date: Fri, 12 Feb 2010 01:30:21 +0000 Subject: Add a new pass on machine instructions to optimize away PHI cycles that reduce down to a single value. InstCombine already does this transformation but DAG legalization may introduce new opportunities. This has turned out to be important for ARM where 64-bit values are split up during type legalization: InstCombine is not able to remove the PHI cycles on the 64-bit values but the separate 32-bit values can be optimized. I measured the compile time impact of this (running llc on 176.gcc) and it was not significant. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95951 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/LLVMTargetMachine.cpp | 1 + 1 file changed, 1 insertion(+) (limited to 'lib/CodeGen/LLVMTargetMachine.cpp') diff --git a/lib/CodeGen/LLVMTargetMachine.cpp b/lib/CodeGen/LLVMTargetMachine.cpp index 40e015067f..3c12afaacf 100644 --- a/lib/CodeGen/LLVMTargetMachine.cpp +++ b/lib/CodeGen/LLVMTargetMachine.cpp @@ -299,6 +299,7 @@ bool LLVMTargetMachine::addCommonCodeGenPasses(PassManagerBase &PM, if (OptLevel != CodeGenOpt::None) { PM.add(createOptimizeExtsPass()); + PM.add(createOptimizePHIsPass()); if (!DisableMachineLICM) PM.add(createMachineLICMPass()); if (!DisableMachineSink) -- cgit v1.2.3