diff options
| author | Chris Lattner <sabre@nondot.org> | 2004-11-14 07:33:16 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2004-11-14 07:33:16 +0000 |
| commit | 711b3402aafd607eeb9ec56395c78e98fe491e76 (patch) | |
| tree | 17e7ae5d3ab04b43de98a949885ed951a69c347d /lib | |
| parent | 6739eae7ea45672a82029ac0a907c97ec1fe6dc5 (diff) | |
Transform this:
%X = alloca ...
%Y = alloca ...
X == Y
into false. This allows us to simplify some stuff in eon (and probably
many other C++ programs) where operator= was checking for self assignment.
Folding this allows us to SROA several additional structs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17735 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Transforms/Scalar/InstructionCombining.cpp | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index 5af9aee165..f1c1c3194b 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -1870,12 +1870,14 @@ Instruction *InstCombiner::visitSetCondInst(BinaryOperator &I) { if (isa<UndefValue>(Op1)) // X setcc undef -> undef return ReplaceInstUsesWith(I, UndefValue::get(Type::BoolTy)); - // setcc <global/alloca*>, 0 - Global/Stack value addresses are never null! - if (isa<ConstantPointerNull>(Op1) && - (isa<GlobalValue>(Op0) || isa<AllocaInst>(Op0))) + // setcc <global/alloca*/null>, <global/alloca*/null> - Global/Stack value + // addresses never equal each other! We already know that Op0 != Op1. + if ((isa<GlobalValue>(Op0) || isa<AllocaInst>(Op0) || + isa<ConstantPointerNull>(Op0)) && + (isa<GlobalValue>(Op1) || isa<AllocaInst>(Op1) || + isa<ConstantPointerNull>(Op1))) return ReplaceInstUsesWith(I, ConstantBool::get(!isTrueWhenEqual(I))); - // setcc's with boolean values can always be turned into bitwise operations if (Ty == Type::BoolTy) { switch (I.getOpcode()) { |