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[ValueTracking] Add abs intrinsics support to computeConstantRange() 

Implementation is the same as for SPF_ABS.
This commit is contained in:
Nikita Popov 2020-08-12 22:26:12 +02:00
parent 6446c11840
commit eba5f5f798
3 changed files with 12 additions and 8 deletions
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8
llvm/lib/Analysis/ValueTracking.cpp
View File

@ -6441,6 +6441,14 @@ static void setLimitsForIntrinsic(const IntrinsicInst &II, APInt &Lower,
llvm_unreachable("Must be min/max intrinsic");
}
break;
case Intrinsic::abs:
// If abs of SIGNED_MIN is poison, then the result is [0..SIGNED_MAX],
// otherwise it is [0..SIGNED_MIN], as -SIGNED_MIN == SIGNED_MIN.
if (match(II.getOperand(1), m_One()))
Upper = APInt::getSignedMaxValue(Width) + 1;
else
Upper = APInt::getSignedMinValue(Width) + 1;
break;
default:
break;
}

4
llvm/test/Transforms/InstCombine/abs-intrinsic.ll
View File

@ -63,7 +63,7 @@ define i32 @abs_signbits(i30 %x) {
; CHECK-LABEL: @abs_signbits(
; CHECK-NEXT: [[EXT:%.*]] = sext i30 [[X:%.*]] to i32
; CHECK-NEXT: [[ABS:%.*]] = call i32 @llvm.abs.i32(i32 [[EXT]], i1 false)
; CHECK-NEXT: [[ADD:%.*]] = add nsw i32 [[ABS]], 1
; CHECK-NEXT: [[ADD:%.*]] = add nuw nsw i32 [[ABS]], 1
; CHECK-NEXT: ret i32 [[ADD]]
;
%ext = sext i30 %x to i32
@ -76,7 +76,7 @@ define <4 x i32> @abs_signbits_vec(<4 x i30> %x) {
; CHECK-LABEL: @abs_signbits_vec(
; CHECK-NEXT: [[EXT:%.*]] = sext <4 x i30> [[X:%.*]] to <4 x i32>
; CHECK-NEXT: [[ABS:%.*]] = call <4 x i32> @llvm.abs.v4i32(<4 x i32> [[EXT]], i1 false)
; CHECK-NEXT: [[ADD:%.*]] = add nsw <4 x i32> [[ABS]], <i32 1, i32 1, i32 1, i32 1>
; CHECK-NEXT: [[ADD:%.*]] = add nuw nsw <4 x i32> [[ABS]], <i32 1, i32 1, i32 1, i32 1>
; CHECK-NEXT: ret <4 x i32> [[ADD]]
;
%ext = sext <4 x i30> %x to <4 x i32>

8
llvm/test/Transforms/InstSimplify/abs_intrinsic.ll
View File

@ -186,9 +186,7 @@ define <4 x i1> @abs_known_not_int_min_vec(<4 x i32> %x) {
; If it's >= 0 it should be >= -1 as well.
define i1 @abs_nsw_sge_neg(i32 %x) {
; CHECK-LABEL: @abs_nsw_sge_neg(
; CHECK-NEXT: [[ABS:%.*]] = call i32 @llvm.abs.i32(i32 [[X:%.*]], i1 true)
; CHECK-NEXT: [[C:%.*]] = icmp sge i32 [[ABS]], -1
; CHECK-NEXT: ret i1 [[C]]
; CHECK-NEXT: ret i1 true
;
%abs = call i32 @llvm.abs.i32(i32 %x, i1 true)
%c = icmp sge i32 %abs, -1
@ -197,9 +195,7 @@ define i1 @abs_nsw_sge_neg(i32 %x) {
define i1 @abs_ule_int_min(i8 %x) {
; CHECK-LABEL: @abs_ule_int_min(
; CHECK-NEXT: [[ABS:%.*]] = call i8 @llvm.abs.i8(i8 [[X:%.*]], i1 false)
; CHECK-NEXT: [[C:%.*]] = icmp ule i8 [[ABS]], -128
; CHECK-NEXT: ret i1 [[C]]
; CHECK-NEXT: ret i1 true
;
%abs = call i8 @llvm.abs.i8(i8 %x, i1 false)
%c = icmp ule i8 %abs, 128