diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Transforms/Scalar/CodeGenPrepare.cpp | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/lib/Transforms/Scalar/CodeGenPrepare.cpp b/lib/Transforms/Scalar/CodeGenPrepare.cpp index 47e60cd..8da0912 100644 --- a/lib/Transforms/Scalar/CodeGenPrepare.cpp +++ b/lib/Transforms/Scalar/CodeGenPrepare.cpp @@ -36,7 +36,7 @@ using namespace llvm; namespace { cl::opt<bool> OptExtUses("optimize-ext-uses", - cl::init(false), cl::Hidden); + cl::init(true), cl::Hidden); } namespace { @@ -929,6 +929,10 @@ bool CodeGenPrepare::OptimizeExtUses(Instruction *I) { if (Src->hasOneUse()) return false; + // Only do this xform is truncating is free. + if (!TLI->isTruncateFree(I->getType(), Src->getType())) + return false; + // Only safe to perform the optimization if the source is also defined in // this block. if (!isa<Instruction>(Src) || DefBB != cast<Instruction>(Src)->getParent()) @@ -952,8 +956,11 @@ bool CodeGenPrepare::OptimizeExtUses(Instruction *I) { for (Value::use_iterator UI = Src->use_begin(), E = Src->use_end(); UI != E; ++UI) { Instruction *User = cast<Instruction>(*UI); - if (User->getParent() == DefBB) continue; - if (isa<PHINode>(User)) + BasicBlock *UserBB = User->getParent(); + if (UserBB == DefBB) continue; + // Be conservative. We don't want this xform to end up introducing + // reloads just before load / store instructions. + if (isa<PHINode>(User) || isa<LoadInst>(User) || isa<StoreInst>(User)) return false; } |