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Fix folding of icmp's of i1 where the comparison is signed. The code

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was using the algorithm for folding unsigned comparisons which is
completely wrong.  This has been broken since the signless types change.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53444 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2008-07-11 04:20:58 +00:00
parent f299184565
commit 85b5eb0505
2 changed files with 33 additions and 12 deletions
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34
lib/Transforms/Scalar/InstructionCombining.cpp
View File

@ -5196,34 +5196,46 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) {
if (Ty == Type::Int1Ty) {
switch (I.getPredicate()) {
default: assert(0 && "Invalid icmp instruction!");
case ICmpInst::ICMP_EQ: { // icmp eq bool %A, %B -> ~(A^B)
case ICmpInst::ICMP_EQ: { // icmp eq i1 A, B -> ~(A^B)
Instruction *Xor = BinaryOperator::CreateXor(Op0, Op1, I.getName()+"tmp");
InsertNewInstBefore(Xor, I);
return BinaryOperator::CreateNot(Xor);
}
case ICmpInst::ICMP_NE: // icmp eq bool %A, %B -> A^B
case ICmpInst::ICMP_NE: // icmp eq i1 A, B -> A^B
return BinaryOperator::CreateXor(Op0, Op1);
case ICmpInst::ICMP_UGT:
case ICmpInst::ICMP_SGT:
std::swap(Op0, Op1); // Change icmp gt -> icmp lt
std::swap(Op0, Op1); // Change icmp ugt -> icmp ult
// FALL THROUGH
case ICmpInst::ICMP_ULT:
case ICmpInst::ICMP_SLT: { // icmp lt bool A, B -> ~X & Y
case ICmpInst::ICMP_ULT:{ // icmp ult i1 A, B -> ~A & B
Instruction *Not = BinaryOperator::CreateNot(Op0, I.getName()+"tmp");
InsertNewInstBefore(Not, I);
return BinaryOperator::CreateAnd(Not, Op1);
}
case ICmpInst::ICMP_UGE:
case ICmpInst::ICMP_SGE:
std::swap(Op0, Op1); // Change icmp ge -> icmp le
case ICmpInst::ICMP_SGT:
std::swap(Op0, Op1); // Change icmp sgt -> icmp slt
// FALL THROUGH
case ICmpInst::ICMP_ULE:
case ICmpInst::ICMP_SLE: { // icmp le bool %A, %B -> ~A | B
case ICmpInst::ICMP_SLT: { // icmp slt i1 A, B -> A & ~B
Instruction *Not = BinaryOperator::CreateNot(Op1, I.getName()+"tmp");
InsertNewInstBefore(Not, I);
return BinaryOperator::CreateAnd(Not, Op0);
}
case ICmpInst::ICMP_UGE:
std::swap(Op0, Op1); // Change icmp uge -> icmp ule
// FALL THROUGH
case ICmpInst::ICMP_ULE: { // icmp ule i1 A, B -> ~A | B
Instruction *Not = BinaryOperator::CreateNot(Op0, I.getName()+"tmp");
InsertNewInstBefore(Not, I);
return BinaryOperator::CreateOr(Not, Op1);
}
case ICmpInst::ICMP_SGE:
std::swap(Op0, Op1); // Change icmp sge -> icmp sle
// FALL THROUGH
case ICmpInst::ICMP_SLE: { // icmp sle i1 A, B -> A | ~B
Instruction *Not = BinaryOperator::CreateNot(Op1, I.getName()+"tmp");
InsertNewInstBefore(Not, I);
return BinaryOperator::CreateOr(Not, Op0);
}
}
}

11
test/Transforms/InstCombine/2008-07-10-CastSextBool.ll
View File

@ -1,8 +1,17 @@
; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep {%C = xor i1 %A, true}
; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep {ret i1 false}
; PR2539
define i1 @test(i1 %A) {
define i1 @test1(i1 %A) {
%B = zext i1 %A to i32
%C = icmp slt i32 %B, 1
ret i1 %C
}
define i1 @test2(i1 zeroext %b) {
entry:
%cmptmp = icmp slt i1 %b, true ; <i1> [#uses=1]
ret i1 %cmptmp
}