diff options
| author | Jakob Stoklund Olesen <stoklund@2pi.dk> | 2009-11-30 22:55:54 +0000 |
|---|---|---|
| committer | Jakob Stoklund Olesen <stoklund@2pi.dk> | 2009-11-30 22:55:54 +0000 |
| commit | ce7a663140e6e67cf5ef7091e076e8541300c15a (patch) | |
| tree | 1cd89c92d53bdb96df8824ce5c153900845c7334 | |
| parent | b25846e1807ab8cb4cc3594458283947fb9e9e39 (diff) | |
New virtual registers created for spill intervals should inherit allocation hints from the original register.
This helps us avoid silly copies when rematting values that are copied to a physical register:
leaq _.str44(%rip), %rcx
movq %rcx, %rsi
call _strcmp
becomes:
leaq _.str44(%rip), %rsi
call _strcmp
The coalescer will not touch the movq because that would tie down the physical register.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90163 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/CodeGen/LiveIntervalAnalysis.cpp | 6 | ||||
| -rw-r--r-- | test/CodeGen/X86/2008-08-05-SpillerBug.ll | 2 |
2 files changed, 7 insertions, 1 deletions
diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp index 4412c1b020..24adf364e7 100644 --- a/lib/CodeGen/LiveIntervalAnalysis.cpp +++ b/lib/CodeGen/LiveIntervalAnalysis.cpp @@ -1095,6 +1095,12 @@ rewriteInstructionForSpills(const LiveInterval &li, const VNInfo *VNI, NewVReg = mri_->createVirtualRegister(rc); vrm.grow(); CreatedNewVReg = true; + + // The new virtual register should get the same allocation hints as the + // old one. + std::pair<unsigned, unsigned> Hint = mri_->getRegAllocationHint(Reg); + if (Hint.first || Hint.second) + mri_->setRegAllocationHint(NewVReg, Hint.first, Hint.second); } if (!TryFold) diff --git a/test/CodeGen/X86/2008-08-05-SpillerBug.ll b/test/CodeGen/X86/2008-08-05-SpillerBug.ll index 1d166f4881..67e14ffae5 100644 --- a/test/CodeGen/X86/2008-08-05-SpillerBug.ll +++ b/test/CodeGen/X86/2008-08-05-SpillerBug.ll @@ -1,4 +1,4 @@ -; RUN: llc < %s -mtriple=i386-apple-darwin -disable-fp-elim -stats |& grep asm-printer | grep 59 +; RUN: llc < %s -mtriple=i386-apple-darwin -disable-fp-elim -stats |& grep asm-printer | grep 58 ; PR2568 @g_3 = external global i16 ; <i16*> [#uses=1] |