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Code that checks WillNotOverflowSignedAdd before creating an Add 

can safely use the NSW bit on the Add.

llvm-svn: 85164
This commit is contained in:
Dan Gohman 2009-10-26 22:14:22 +00:00
parent 12e678d550
commit 672927f393
3 changed files with 10 additions and 10 deletions
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16
llvm/lib/Transforms/Scalar/InstructionCombining.cpp
View File

@ -2420,8 +2420,8 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) {
ConstantExpr::getSExt(CI, I.getType()) == RHSC &&
WillNotOverflowSignedAdd(LHSConv->getOperand(0), CI)) {
// Insert the new, smaller add.
Value *NewAdd = Builder->CreateAdd(LHSConv->getOperand(0),
CI, "addconv");
Value *NewAdd = Builder->CreateNSWAdd(LHSConv->getOperand(0),
CI, "addconv");
return new SExtInst(NewAdd, I.getType());
}
}
@ -2436,8 +2436,8 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) {
WillNotOverflowSignedAdd(LHSConv->getOperand(0),
RHSConv->getOperand(0))) {
// Insert the new integer add.
Value *NewAdd = Builder->CreateAdd(LHSConv->getOperand(0),
RHSConv->getOperand(0), "addconv");
Value *NewAdd = Builder->CreateNSWAdd(LHSConv->getOperand(0),
RHSConv->getOperand(0), "addconv");
return new SExtInst(NewAdd, I.getType());
}
}
@ -2493,8 +2493,8 @@ Instruction *InstCombiner::visitFAdd(BinaryOperator &I) {
ConstantExpr::getSIToFP(CI, I.getType()) == CFP &&
WillNotOverflowSignedAdd(LHSConv->getOperand(0), CI)) {
// Insert the new integer add.
Value *NewAdd = Builder->CreateAdd(LHSConv->getOperand(0),
CI, "addconv");
Value *NewAdd = Builder->CreateNSWAdd(LHSConv->getOperand(0),
CI, "addconv");
return new SIToFPInst(NewAdd, I.getType());
}
}
@ -2509,8 +2509,8 @@ Instruction *InstCombiner::visitFAdd(BinaryOperator &I) {
WillNotOverflowSignedAdd(LHSConv->getOperand(0),
RHSConv->getOperand(0))) {
// Insert the new integer add.
Value *NewAdd = Builder->CreateAdd(LHSConv->getOperand(0),
RHSConv->getOperand(0), "addconv");
Value *NewAdd = Builder->CreateNSWAdd(LHSConv->getOperand(0),
RHSConv->getOperand(0), "addconv");
return new SIToFPInst(NewAdd, I.getType());
}
}

2
llvm/test/Transforms/InstCombine/add-shrink.ll
View File

@ -1,4 +1,4 @@
; RUN: opt < %s -instcombine -S | grep {add i32}
; RUN: opt < %s -instcombine -S | grep {add nsw i32}
; RUN: opt < %s -instcombine -S | grep sext | count 1
; Should only have one sext and the add should be i32 instead of i64.

2
llvm/test/Transforms/InstCombine/add-sitofp.ll
View File

@ -1,4 +1,4 @@
; RUN: opt < %s -instcombine -S | grep {add i32}
; RUN: opt < %s -instcombine -S | grep {add nsw i32}
define double @x(i32 %a, i32 %b) nounwind {
%m = lshr i32 %a, 24