[llvm] r351645 - [InstCombine] Simplify cttz/ctlz + icmp ugt/ult
Nikita Popov via llvm-commits
llvm-commits at lists.llvm.org
Sat Jan 19 01:56:01 PST 2019
Author: nikic
Date: Sat Jan 19 01:56:01 2019
New Revision: 351645
URL: http://llvm.org/viewvc/llvm-project?rev=351645&view=rev
Log:
[InstCombine] Simplify cttz/ctlz + icmp ugt/ult
Followup to D55745, this time handling comparisons with ugt and ult
predicates (which are the canonical forms for non-equality predicates).
For ctlz we can convert into a simple icmp, for cttz we can convert
into a mask check.
Differential Revision: https://reviews.llvm.org/D56355
Modified:
llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
llvm/trunk/lib/Transforms/InstCombine/InstCombineInternal.h
llvm/trunk/test/Transforms/InstCombine/cmp-intrinsic.ll
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp?rev=351645&r1=351644&r2=351645&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp Sat Jan 19 01:56:01 2019
@@ -2610,8 +2610,9 @@ Instruction *InstCombiner::foldICmpInstW
return I;
}
- if (Instruction *I = foldICmpIntrinsicWithConstant(Cmp, *C))
- return I;
+ if (auto *II = dyn_cast<IntrinsicInst>(Cmp.getOperand(0)))
+ if (Instruction *I = foldICmpIntrinsicWithConstant(Cmp, II, *C))
+ return I;
return nullptr;
}
@@ -2755,14 +2756,10 @@ Instruction *InstCombiner::foldICmpBinOp
return nullptr;
}
-/// Fold an icmp with LLVM intrinsic and constant operand: icmp Pred II, C.
-Instruction *InstCombiner::foldICmpIntrinsicWithConstant(ICmpInst &Cmp,
- const APInt &C) {
- IntrinsicInst *II = dyn_cast<IntrinsicInst>(Cmp.getOperand(0));
- if (!II || !Cmp.isEquality())
- return nullptr;
-
- // Handle icmp {eq|ne} <intrinsic>, Constant.
+/// Fold an equality icmp with LLVM intrinsic and constant operand.
+Instruction *InstCombiner::foldICmpEqIntrinsicWithConstant(ICmpInst &Cmp,
+ IntrinsicInst *II,
+ const APInt &C) {
Type *Ty = II->getType();
unsigned BitWidth = C.getBitWidth();
switch (II->getIntrinsicID()) {
@@ -2815,6 +2812,65 @@ Instruction *InstCombiner::foldICmpIntri
}
break;
}
+ default:
+ break;
+ }
+
+ return nullptr;
+}
+
+/// Fold an icmp with LLVM intrinsic and constant operand: icmp Pred II, C.
+Instruction *InstCombiner::foldICmpIntrinsicWithConstant(ICmpInst &Cmp,
+ IntrinsicInst *II,
+ const APInt &C) {
+ if (Cmp.isEquality())
+ return foldICmpEqIntrinsicWithConstant(Cmp, II, C);
+
+ Type *Ty = II->getType();
+ unsigned BitWidth = C.getBitWidth();
+ switch (II->getIntrinsicID()) {
+ case Intrinsic::ctlz: {
+ // ctlz(0bXXXXXXXX) > 3 -> 0bXXXXXXXX < 0b00010000
+ if (Cmp.getPredicate() == ICmpInst::ICMP_UGT && C.ult(BitWidth)) {
+ unsigned Num = C.getLimitedValue();
+ APInt Limit = APInt::getOneBitSet(BitWidth, BitWidth - Num - 1);
+ return CmpInst::Create(Instruction::ICmp, ICmpInst::ICMP_ULT,
+ II->getArgOperand(0), ConstantInt::get(Ty, Limit));
+ }
+
+ // ctlz(0bXXXXXXXX) < 3 -> 0bXXXXXXXX > 0b00011111
+ if (Cmp.getPredicate() == ICmpInst::ICMP_ULT &&
+ C.uge(1) && C.ule(BitWidth)) {
+ unsigned Num = C.getLimitedValue();
+ APInt Limit = APInt::getLowBitsSet(BitWidth, BitWidth - Num);
+ return CmpInst::Create(Instruction::ICmp, ICmpInst::ICMP_UGT,
+ II->getArgOperand(0), ConstantInt::get(Ty, Limit));
+ }
+ break;
+ }
+ case Intrinsic::cttz: {
+ // Limit to one use to ensure we don't increase instruction count.
+ if (!II->hasOneUse())
+ return nullptr;
+
+ // cttz(0bXXXXXXXX) > 3 -> 0bXXXXXXXX & 0b00001111 == 0
+ if (Cmp.getPredicate() == ICmpInst::ICMP_UGT && C.ult(BitWidth)) {
+ APInt Mask = APInt::getLowBitsSet(BitWidth, C.getLimitedValue() + 1);
+ return CmpInst::Create(Instruction::ICmp, ICmpInst::ICMP_EQ,
+ Builder.CreateAnd(II->getArgOperand(0), Mask),
+ ConstantInt::getNullValue(Ty));
+ }
+
+ // cttz(0bXXXXXXXX) < 3 -> 0bXXXXXXXX & 0b00000111 != 0
+ if (Cmp.getPredicate() == ICmpInst::ICMP_ULT &&
+ C.uge(1) && C.ule(BitWidth)) {
+ APInt Mask = APInt::getLowBitsSet(BitWidth, C.getLimitedValue());
+ return CmpInst::Create(Instruction::ICmp, ICmpInst::ICMP_NE,
+ Builder.CreateAnd(II->getArgOperand(0), Mask),
+ ConstantInt::getNullValue(Ty));
+ }
+ break;
+ }
default:
break;
}
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineInternal.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineInternal.h?rev=351645&r1=351644&r2=351645&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineInternal.h (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineInternal.h Sat Jan 19 01:56:01 2019
@@ -903,7 +903,10 @@ private:
Instruction *foldICmpBinOpEqualityWithConstant(ICmpInst &Cmp,
BinaryOperator *BO,
const APInt &C);
- Instruction *foldICmpIntrinsicWithConstant(ICmpInst &ICI, const APInt &C);
+ Instruction *foldICmpIntrinsicWithConstant(ICmpInst &ICI, IntrinsicInst *II,
+ const APInt &C);
+ Instruction *foldICmpEqIntrinsicWithConstant(ICmpInst &ICI, IntrinsicInst *II,
+ const APInt &C);
// Helpers of visitSelectInst().
Instruction *foldSelectExtConst(SelectInst &Sel);
Modified: llvm/trunk/test/Transforms/InstCombine/cmp-intrinsic.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/cmp-intrinsic.ll?rev=351645&r1=351644&r2=351645&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/cmp-intrinsic.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/cmp-intrinsic.ll Sat Jan 19 01:56:01 2019
@@ -149,8 +149,7 @@ define i1 @ctlz_ugt_zero_i32(i32 %x) {
define i1 @ctlz_ugt_one_i32(i32 %x) {
; CHECK-LABEL: @ctlz_ugt_one_i32(
-; CHECK-NEXT: [[LZ:%.*]] = tail call i32 @llvm.ctlz.i32(i32 [[X:%.*]], i1 false), !range !0
-; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i32 [[LZ]], 1
+; CHECK-NEXT: [[CMP:%.*]] = icmp ult i32 [[X:%.*]], 1073741824
; CHECK-NEXT: ret i1 [[CMP]]
;
%lz = tail call i32 @llvm.ctlz.i32(i32 %x, i1 false)
@@ -160,8 +159,7 @@ define i1 @ctlz_ugt_one_i32(i32 %x) {
define i1 @ctlz_ugt_other_i32(i32 %x) {
; CHECK-LABEL: @ctlz_ugt_other_i32(
-; CHECK-NEXT: [[LZ:%.*]] = tail call i32 @llvm.ctlz.i32(i32 [[X:%.*]], i1 false), !range !0
-; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i32 [[LZ]], 16
+; CHECK-NEXT: [[CMP:%.*]] = icmp ult i32 [[X:%.*]], 32768
; CHECK-NEXT: ret i1 [[CMP]]
;
%lz = tail call i32 @llvm.ctlz.i32(i32 %x, i1 false)
@@ -173,7 +171,7 @@ define i1 @ctlz_ugt_other_multiuse_i32(i
; CHECK-LABEL: @ctlz_ugt_other_multiuse_i32(
; CHECK-NEXT: [[LZ:%.*]] = tail call i32 @llvm.ctlz.i32(i32 [[X:%.*]], i1 false), !range !0
; CHECK-NEXT: store i32 [[LZ]], i32* [[P:%.*]], align 4
-; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i32 [[LZ]], 16
+; CHECK-NEXT: [[CMP:%.*]] = icmp ult i32 [[X]], 32768
; CHECK-NEXT: ret i1 [[CMP]]
;
%lz = tail call i32 @llvm.ctlz.i32(i32 %x, i1 false)
@@ -184,8 +182,7 @@ define i1 @ctlz_ugt_other_multiuse_i32(i
define i1 @ctlz_ugt_bw_minus_one_i32(i32 %x) {
; CHECK-LABEL: @ctlz_ugt_bw_minus_one_i32(
-; CHECK-NEXT: [[LZ:%.*]] = tail call i32 @llvm.ctlz.i32(i32 [[X:%.*]], i1 false), !range !0
-; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i32 [[LZ]], 31
+; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[X:%.*]], 0
; CHECK-NEXT: ret i1 [[CMP]]
;
%lz = tail call i32 @llvm.ctlz.i32(i32 %x, i1 false)
@@ -205,8 +202,7 @@ define <2 x i1> @ctlz_ult_one_v2i32(<2 x
define <2 x i1> @ctlz_ult_other_v2i32(<2 x i32> %x) {
; CHECK-LABEL: @ctlz_ult_other_v2i32(
-; CHECK-NEXT: [[LZ:%.*]] = tail call <2 x i32> @llvm.ctlz.v2i32(<2 x i32> [[X:%.*]], i1 false)
-; CHECK-NEXT: [[CMP:%.*]] = icmp ult <2 x i32> [[LZ]], <i32 16, i32 16>
+; CHECK-NEXT: [[CMP:%.*]] = icmp ugt <2 x i32> [[X:%.*]], <i32 65535, i32 65535>
; CHECK-NEXT: ret <2 x i1> [[CMP]]
;
%lz = tail call <2 x i32> @llvm.ctlz.v2i32(<2 x i32> %x, i1 false)
@@ -218,7 +214,7 @@ define <2 x i1> @ctlz_ult_other_multiuse
; CHECK-LABEL: @ctlz_ult_other_multiuse_v2i32(
; CHECK-NEXT: [[LZ:%.*]] = tail call <2 x i32> @llvm.ctlz.v2i32(<2 x i32> [[X:%.*]], i1 false)
; CHECK-NEXT: store <2 x i32> [[LZ]], <2 x i32>* [[P:%.*]], align 8
-; CHECK-NEXT: [[CMP:%.*]] = icmp ult <2 x i32> [[LZ]], <i32 16, i32 16>
+; CHECK-NEXT: [[CMP:%.*]] = icmp ugt <2 x i32> [[X]], <i32 65535, i32 65535>
; CHECK-NEXT: ret <2 x i1> [[CMP]]
;
%lz = tail call <2 x i32> @llvm.ctlz.v2i32(<2 x i32> %x, i1 false)
@@ -229,8 +225,7 @@ define <2 x i1> @ctlz_ult_other_multiuse
define <2 x i1> @ctlz_ult_bw_minus_one_v2i32(<2 x i32> %x) {
; CHECK-LABEL: @ctlz_ult_bw_minus_one_v2i32(
-; CHECK-NEXT: [[LZ:%.*]] = tail call <2 x i32> @llvm.ctlz.v2i32(<2 x i32> [[X:%.*]], i1 false)
-; CHECK-NEXT: [[CMP:%.*]] = icmp ult <2 x i32> [[LZ]], <i32 31, i32 31>
+; CHECK-NEXT: [[CMP:%.*]] = icmp ugt <2 x i32> [[X:%.*]], <i32 1, i32 1>
; CHECK-NEXT: ret <2 x i1> [[CMP]]
;
%lz = tail call <2 x i32> @llvm.ctlz.v2i32(<2 x i32> %x, i1 false)
@@ -240,8 +235,7 @@ define <2 x i1> @ctlz_ult_bw_minus_one_v
define <2 x i1> @ctlz_ult_bitwidth_v2i32(<2 x i32> %x) {
; CHECK-LABEL: @ctlz_ult_bitwidth_v2i32(
-; CHECK-NEXT: [[LZ:%.*]] = tail call <2 x i32> @llvm.ctlz.v2i32(<2 x i32> [[X:%.*]], i1 false)
-; CHECK-NEXT: [[CMP:%.*]] = icmp ult <2 x i32> [[LZ]], <i32 32, i32 32>
+; CHECK-NEXT: [[CMP:%.*]] = icmp ne <2 x i32> [[X:%.*]], zeroinitializer
; CHECK-NEXT: ret <2 x i1> [[CMP]]
;
%lz = tail call <2 x i32> @llvm.ctlz.v2i32(<2 x i32> %x, i1 false)
@@ -359,8 +353,8 @@ define i1 @cttz_ugt_zero_i33(i33 %x) {
define i1 @cttz_ugt_one_i33(i33 %x) {
; CHECK-LABEL: @cttz_ugt_one_i33(
-; CHECK-NEXT: [[TZ:%.*]] = tail call i33 @llvm.cttz.i33(i33 [[X:%.*]], i1 false), !range !1
-; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i33 [[TZ]], 1
+; CHECK-NEXT: [[TMP1:%.*]] = and i33 [[X:%.*]], 3
+; CHECK-NEXT: [[CMP:%.*]] = icmp eq i33 [[TMP1]], 0
; CHECK-NEXT: ret i1 [[CMP]]
;
%tz = tail call i33 @llvm.cttz.i33(i33 %x, i1 false)
@@ -370,8 +364,8 @@ define i1 @cttz_ugt_one_i33(i33 %x) {
define i1 @cttz_ugt_other_i33(i33 %x) {
; CHECK-LABEL: @cttz_ugt_other_i33(
-; CHECK-NEXT: [[TZ:%.*]] = tail call i33 @llvm.cttz.i33(i33 [[X:%.*]], i1 false), !range !1
-; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i33 [[TZ]], 16
+; CHECK-NEXT: [[TMP1:%.*]] = and i33 [[X:%.*]], 131071
+; CHECK-NEXT: [[CMP:%.*]] = icmp eq i33 [[TMP1]], 0
; CHECK-NEXT: ret i1 [[CMP]]
;
%tz = tail call i33 @llvm.cttz.i33(i33 %x, i1 false)
@@ -394,8 +388,7 @@ define i1 @cttz_ugt_other_multiuse_i33(i
define i1 @cttz_ugt_bw_minus_one_i33(i33 %x) {
; CHECK-LABEL: @cttz_ugt_bw_minus_one_i33(
-; CHECK-NEXT: [[TZ:%.*]] = tail call i33 @llvm.cttz.i33(i33 [[X:%.*]], i1 false), !range !1
-; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i33 [[TZ]], 32
+; CHECK-NEXT: [[CMP:%.*]] = icmp eq i33 [[X:%.*]], 0
; CHECK-NEXT: ret i1 [[CMP]]
;
%tz = tail call i33 @llvm.cttz.i33(i33 %x, i1 false)
@@ -415,8 +408,8 @@ define <2 x i1> @cttz_ult_one_v2i32(<2 x
define <2 x i1> @cttz_ult_other_v2i32(<2 x i32> %x) {
; CHECK-LABEL: @cttz_ult_other_v2i32(
-; CHECK-NEXT: [[TZ:%.*]] = tail call <2 x i32> @llvm.cttz.v2i32(<2 x i32> [[X:%.*]], i1 false)
-; CHECK-NEXT: [[CMP:%.*]] = icmp ult <2 x i32> [[TZ]], <i32 16, i32 16>
+; CHECK-NEXT: [[TMP1:%.*]] = and <2 x i32> [[X:%.*]], <i32 65535, i32 65535>
+; CHECK-NEXT: [[CMP:%.*]] = icmp ne <2 x i32> [[TMP1]], zeroinitializer
; CHECK-NEXT: ret <2 x i1> [[CMP]]
;
%tz = tail call <2 x i32> @llvm.cttz.v2i32(<2 x i32> %x, i1 false)
@@ -439,8 +432,8 @@ define <2 x i1> @cttz_ult_other_multiuse
define <2 x i1> @cttz_ult_bw_minus_one_v2i32(<2 x i32> %x) {
; CHECK-LABEL: @cttz_ult_bw_minus_one_v2i32(
-; CHECK-NEXT: [[TZ:%.*]] = tail call <2 x i32> @llvm.cttz.v2i32(<2 x i32> [[X:%.*]], i1 false)
-; CHECK-NEXT: [[CMP:%.*]] = icmp ult <2 x i32> [[TZ]], <i32 31, i32 31>
+; CHECK-NEXT: [[TMP1:%.*]] = and <2 x i32> [[X:%.*]], <i32 2147483647, i32 2147483647>
+; CHECK-NEXT: [[CMP:%.*]] = icmp ne <2 x i32> [[TMP1]], zeroinitializer
; CHECK-NEXT: ret <2 x i1> [[CMP]]
;
%tz = tail call <2 x i32> @llvm.cttz.v2i32(<2 x i32> %x, i1 false)
@@ -450,8 +443,7 @@ define <2 x i1> @cttz_ult_bw_minus_one_v
define <2 x i1> @cttz_ult_bitwidth_v2i32(<2 x i32> %x) {
; CHECK-LABEL: @cttz_ult_bitwidth_v2i32(
-; CHECK-NEXT: [[TZ:%.*]] = tail call <2 x i32> @llvm.cttz.v2i32(<2 x i32> [[X:%.*]], i1 false)
-; CHECK-NEXT: [[CMP:%.*]] = icmp ult <2 x i32> [[TZ]], <i32 32, i32 32>
+; CHECK-NEXT: [[CMP:%.*]] = icmp ne <2 x i32> [[X:%.*]], zeroinitializer
; CHECK-NEXT: ret <2 x i1> [[CMP]]
;
%tz = tail call <2 x i32> @llvm.cttz.v2i32(<2 x i32> %x, i1 false)
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