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remove a couple more unsafe xforms in the face of overflow. 

llvm-svn: 45613
This commit is contained in:
Chris Lattner 2008-01-05 01:22:42 +00:00
parent db026d703b
commit e666bc272d
2 changed files with 0 additions and 34 deletions
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9
llvm/lib/Transforms/Scalar/InstructionCombining.cpp
View File

@ -4865,10 +4865,6 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) {
return new ICmpInst(ICmpInst::ICMP_NE, Op0, Op1);
if (isMinValuePlusOne(CI,true)) // A <s MIN+1 -> A == MIN
return new ICmpInst(ICmpInst::ICMP_EQ, Op0, SubOne(CI));
// (icmp slt (sub A B) 1) -> (icmp sle A B)
if (CI->isOne() && match(Op0, m_Sub(m_Value(A), m_Value(B))))
return new ICmpInst(ICmpInst::ICMP_SLE, A, B);
break;
case ICmpInst::ICMP_UGT:
@ -4892,11 +4888,6 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) {
return new ICmpInst(ICmpInst::ICMP_NE, Op0, Op1);
if (isMaxValueMinusOne(CI, true)) // A >s MAX-1 -> A == MAX
return new ICmpInst(ICmpInst::ICMP_EQ, Op0, AddOne(CI));
// (icmp sgt (sub A B) -1) -> (icmp sge A B)
if (CI->getValue().getSExtValue() == -1 &&
match(Op0, m_Sub(m_Value(A), m_Value(B))))
return new ICmpInst(ICmpInst::ICMP_SGE, A, B);
break;
case ICmpInst::ICMP_ULE:

25
llvm/test/Transforms/InstCombine/2007-12-19-IcmpSub.ll
View File

@ -1,25 +0,0 @@
; RUN: llvm-as < %s | opt -instcombine | llvm-dis | not grep {sub}
define i32 @foo(i32 %a) {
entry:
%tmp2 = sub i32 99, %a ; <i32> [#uses=1]
%tmp3 = icmp sgt i32 %tmp2, -1 ; <i1> [#uses=1]
%retval = select i1 %tmp3, i32 %a, i32 0 ; <i32> [#uses=1]
ret i32 %retval
}
define i32 @bar(i32 %a) {
entry:
%tmp2 = sub i32 99, %a ; <i32> [#uses=1]
%tmp3 = icmp sge i32 %tmp2, 0; <i1> [#uses=1]
%retval = select i1 %tmp3, i32 %a, i32 0 ; <i32> [#uses=1]
ret i32 %retval
}
define i32 @baz(i32 %a) {
entry:
%tmp2 = sub i32 99, %a ; <i32> [#uses=1]
%tmp3 = icmp slt i32 %tmp2, 1 ; <i1> [#uses=1]
%retval = select i1 %tmp3, i32 %a, i32 0 ; <i32> [#uses=1]
ret i32 %retval
}