RPCS3/llvm-mirror
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-10-22 12:33:33 +02:00
Code Issues Projects Releases Wiki Activity

[InstCombine] use m_APInt to allow icmp X, C folds for splat constant vectors

Browse Source 
Of course, we really need to refactor and fix all of the cmp predicates, 
but this one is interesting because without it, we later perform an 
information-losing transform of icmp (shl 1, Y), C, and we can't recover
the better fold.

llvm-svn: 279263
This commit is contained in:
Sanjay Patel 2016-08-19 15:40:44 +00:00
parent 6efdc4d959
commit e8714eaca2
2 changed files with 16 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
lib/Transforms/InstCombine/InstCombineCompares.cpp
View File

@ -3622,25 +3622,30 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) {
Constant::getAllOnesValue(Op0->getType()));
}
break;
case ICmpInst::ICMP_UGT:
case ICmpInst::ICMP_UGT: {
if (Op0Min.ugt(Op1Max)) // A >u B -> true if min(A) > max(B)
return replaceInstUsesWith(I, ConstantInt::getTrue(I.getType()));
if (Op0Max.ule(Op1Min)) // A >u B -> false if max(A) <= max(B)
return replaceInstUsesWith(I, ConstantInt::getFalse(I.getType()));
if (Op1Max == Op0Min) // A >u B -> A != B if min(A) == max(B)
return new ICmpInst(ICmpInst::ICMP_NE, Op0, Op1);
if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) {
if (Op1Min == Op0Max-1) // A >u C -> A == C+1 if max(a)-1 == C
const APInt *CmpC;
if (match(Op1, m_APInt(CmpC))) {
// A >u C -> A == C+1 if max(a)-1 == C
if (*CmpC == Op0Max - 1)
return new ICmpInst(ICmpInst::ICMP_EQ, Op0,
Builder->getInt(CI->getValue()+1));
ConstantInt::get(Op1->getType(), *CmpC + 1));
// (x >u 2147483647) -> (x <s 0) -> true if sign bit set
if (CI->isMaxValue(true))
if (CmpC->isMaxSignedValue())
return new ICmpInst(ICmpInst::ICMP_SLT, Op0,
Constant::getNullValue(Op0->getType()));
}
break;
}
case ICmpInst::ICMP_SLT:
if (Op0Max.slt(Op1Min)) // A <s B -> true if max(A) < min(C)
return replaceInstUsesWith(I, ConstantInt::getTrue(I.getType()));

8
test/Transforms/InstCombine/icmp.ll
View File

@ -1672,7 +1672,7 @@ define i1 @icmp_shl_1_V_uge_2147483648(i32 %V) {
define <2 x i1> @icmp_shl_1_V_uge_2147483648_vec(<2 x i32> %V) {
; CHECK-LABEL: @icmp_shl_1_V_uge_2147483648_vec(
; CHECK-NEXT: [[SHL:%.*]] = shl <2 x i32> <i32 1, i32 1>, %V
; CHECK-NEXT: [[CMP:%.*]] = icmp ugt <2 x i32> [[SHL]], <i32 2147483647, i32 2147483647>
; CHECK-NEXT: [[CMP:%.*]] = icmp slt <2 x i32> [[SHL]], zeroinitializer
; CHECK-NEXT: ret <2 x i1> [[CMP]]
;
%shl = shl <2 x i32> <i32 1, i32 1>, %V
@ -2591,6 +2591,10 @@ define i1 @ugtMaxSignedVal(i8 %a) {
}
define <2 x i1> @ugtMaxSignedValVec(<2 x i8> %a) {
; CHECK-LABEL: @ugtMaxSignedValVec(
; CHECK-NEXT: [[CMP:%.*]] = icmp slt <2 x i8> %a, zeroinitializer
; CHECK-NEXT: ret <2 x i1> [[CMP]]
;
%cmp = icmp ugt <2 x i8> %a, <i8 127, i8 127>
ret <2 x i1> %cmp
}
@ -2609,7 +2613,7 @@ define i1 @ugtKnownBits(i8 %a) {
define <2 x i1> @ugtKnownBitsVec(<2 x i8> %a) {
; CHECK-LABEL: @ugtKnownBitsVec(
; CHECK-NEXT: [[B:%.*]] = and <2 x i8> %a, <i8 17, i8 17>
; CHECK-NEXT: [[CMP:%.*]] = icmp ugt <2 x i8> [[B]], <i8 16, i8 16>
; CHECK-NEXT: [[CMP:%.*]] = icmp eq <2 x i8> [[B]], <i8 17, i8 17>
; CHECK-NEXT: ret <2 x i1> [[CMP]]
;
%b = and <2 x i8> %a, <i8 17, i8 17>