RPCS3/llvm-mirror
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2025-01-17 00:57:54 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Improved fix for abs(val) != 0 to check other similar case. Also fixed style issues and confusing comment

Browse Source 
llvm-svn: 145618
This commit is contained in:
Pete Cooper 2011-12-01 19:13:26 +00:00
parent 78bd9e81b4
commit c708e83499
2 changed files with 22 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
lib/Transforms/InstCombine/InstCombineCompares.cpp
View File

@ -1796,15 +1796,19 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) {
return ReplaceInstUsesWith(I, V);
// comparing -val or val with non-zero is the same as just comparing val
// ie, (val != 0) == (-val != 0)
// ie, abs(val) != 0 -> val != 0
if (I.getPredicate() == ICmpInst::ICMP_NE && match(Op1, m_Zero()))
{
Value *Cond, *SubSrc, *SelectFalse;
if (match(Op0, m_Select(m_Value(Cond), m_Sub(m_Zero(), m_Value(SubSrc)),
Value *Cond, *SelectTrue, *SelectFalse;
if (match(Op0, m_Select(m_Value(Cond), m_Value(SelectTrue),
m_Value(SelectFalse)))) {
if (SubSrc == SelectFalse) {
return CmpInst::Create(Instruction::ICmp, I.getPredicate(),
SubSrc, Op1);
if (Value *V = dyn_castNegVal(SelectTrue)) {
if (V == SelectFalse)
return CmpInst::Create(Instruction::ICmp, I.getPredicate(), V, Op1);
}
else if (Value *V = dyn_castNegVal(SelectFalse)) {
if (V == SelectTrue)
return CmpInst::Create(Instruction::ICmp, I.getPredicate(), V, Op1);
}
}
}

14
test/Transforms/InstCombine/icmp.ll
View File

@ -561,12 +561,22 @@ define i1 @test57(i32 %a) {
}
; rdar://problem/10482509
; CHECK: @cmpabs
; CHECK: @cmpabs1
; CHECK-NEXT: icmp ne
define zeroext i1 @cmpabs(i64 %val) {
define zeroext i1 @cmpabs1(i64 %val) {
%sub = sub nsw i64 0, %val
%cmp = icmp slt i64 %val, 0
%sub.val = select i1 %cmp, i64 %sub, i64 %val
%tobool = icmp ne i64 %sub.val, 0
ret i1 %tobool
}
; CHECK: @cmpabs2
; CHECK-NEXT: icmp ne
define zeroext i1 @cmpabs2(i64 %val) {
%sub = sub nsw i64 0, %val
%cmp = icmp slt i64 %val, 0
%sub.val = select i1 %cmp, i64 %val, i64 %sub
%tobool = icmp ne i64 %sub.val, 0
ret i1 %tobool
}