[llvm] 13f16f4 - [InstCombine] Canonicalize `(icmp eq/ne (and x, C), x)` -> `(icmp eq/ne (and x, ~C), 0)`
Noah Goldstein via llvm-commits
llvm-commits at lists.llvm.org
Thu Jun 29 11:15:08 PDT 2023
Author: Noah Goldstein
Date: 2023-06-29T13:14:37-05:00
New Revision: 13f16f4dea14a5efc4d471e02317b8ffb77a0896
URL: https://github.com/llvm/llvm-project/commit/13f16f4dea14a5efc4d471e02317b8ffb77a0896
DIFF: https://github.com/llvm/llvm-project/commit/13f16f4dea14a5efc4d471e02317b8ffb77a0896.diff
LOG: [InstCombine] Canonicalize `(icmp eq/ne (and x, C), x)` -> `(icmp eq/ne (and x, ~C), 0)`
This increases the likelyhood `x` is single-use and is typically
easier to analyze.
Proofs: https://alive2.llvm.org/ce/z/8ZpS2W
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D154004
Added:
Modified:
llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-eq-to-icmp-ule.ll
llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-ne-to-icmp-ugt.ll
llvm/test/Transforms/InstCombine/icmp-logical.ll
llvm/test/Transforms/InstCombine/select.ll
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
index 03bbd22236ff59..019b7c7d2d5d03 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -4875,6 +4875,21 @@ Instruction *InstCombinerImpl::foldICmpEquality(ICmpInst &I) {
}
}
+ // canoncalize:
+ // (icmp eq/ne (and X, C), X)
+ // -> (icmp eq/ne (and X, ~C), 0)
+ {
+ Constant *CMask;
+ A = nullptr;
+ if (match(Op0, m_OneUse(m_And(m_Specific(Op1), m_ImmConstant(CMask)))))
+ A = Op1;
+ else if (match(Op1, m_OneUse(m_And(m_Specific(Op0), m_ImmConstant(CMask)))))
+ A = Op0;
+ if (A)
+ return new ICmpInst(Pred, Builder.CreateAnd(A, Builder.CreateNot(CMask)),
+ Constant::getNullValue(A->getType()));
+ }
+
if (match(Op1, m_Xor(m_Value(A), m_Value(B))) && (A == Op0 || B == Op0)) {
// A == (A^B) -> B == 0
Value *OtherVal = A == Op0 ? B : A;
diff --git a/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-eq-to-icmp-ule.ll b/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-eq-to-icmp-ule.ll
index 85bb4d51c7ba41..a957fb2d088ef4 100644
--- a/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-eq-to-icmp-ule.ll
+++ b/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-eq-to-icmp-ule.ll
@@ -62,8 +62,8 @@ define <2 x i1> @p2_vec_nonsplat(<2 x i8> %x) {
define <2 x i1> @p2_vec_nonsplat_edgecase0(<2 x i8> %x) {
; CHECK-LABEL: @p2_vec_nonsplat_edgecase0(
-; CHECK-NEXT: [[TMP0:%.*]] = and <2 x i8> [[X:%.*]], <i8 3, i8 0>
-; CHECK-NEXT: [[RET:%.*]] = icmp eq <2 x i8> [[TMP0]], [[X]]
+; CHECK-NEXT: [[TMP1:%.*]] = and <2 x i8> [[X:%.*]], <i8 -4, i8 -1>
+; CHECK-NEXT: [[RET:%.*]] = icmp eq <2 x i8> [[TMP1]], zeroinitializer
; CHECK-NEXT: ret <2 x i1> [[RET]]
;
%tmp0 = and <2 x i8> %x, <i8 3, i8 0>
@@ -179,8 +179,8 @@ define i1 @oneuse0(i8 %x) {
define i1 @n0(i8 %x) {
; CHECK-LABEL: @n0(
-; CHECK-NEXT: [[TMP0:%.*]] = and i8 [[X:%.*]], 4
-; CHECK-NEXT: [[RET:%.*]] = icmp eq i8 [[TMP0]], [[X]]
+; CHECK-NEXT: [[TMP1:%.*]] = and i8 [[X:%.*]], -5
+; CHECK-NEXT: [[RET:%.*]] = icmp eq i8 [[TMP1]], 0
; CHECK-NEXT: ret i1 [[RET]]
;
%tmp0 = and i8 %x, 4 ; power-of-two, but invalid.
@@ -201,8 +201,8 @@ define i1 @n1(i8 %x, i8 %y, i8 %notx) {
define <2 x i1> @n2(<2 x i8> %x) {
; CHECK-LABEL: @n2(
-; CHECK-NEXT: [[TMP0:%.*]] = and <2 x i8> [[X:%.*]], <i8 3, i8 16>
-; CHECK-NEXT: [[RET:%.*]] = icmp eq <2 x i8> [[TMP0]], [[X]]
+; CHECK-NEXT: [[TMP1:%.*]] = and <2 x i8> [[X:%.*]], <i8 -4, i8 -17>
+; CHECK-NEXT: [[RET:%.*]] = icmp eq <2 x i8> [[TMP1]], zeroinitializer
; CHECK-NEXT: ret <2 x i1> [[RET]]
;
%tmp0 = and <2 x i8> %x, <i8 3, i8 16> ; only the first one is valid.
diff --git a/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-ne-to-icmp-ugt.ll b/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-ne-to-icmp-ugt.ll
index 473ae0caabe6be..57361cdf38977c 100644
--- a/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-ne-to-icmp-ugt.ll
+++ b/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-ne-to-icmp-ugt.ll
@@ -62,8 +62,8 @@ define <2 x i1> @p2_vec_nonsplat(<2 x i8> %x) {
define <2 x i1> @p2_vec_nonsplat_edgecase0(<2 x i8> %x) {
; CHECK-LABEL: @p2_vec_nonsplat_edgecase0(
-; CHECK-NEXT: [[TMP0:%.*]] = and <2 x i8> [[X:%.*]], <i8 3, i8 0>
-; CHECK-NEXT: [[RET:%.*]] = icmp ne <2 x i8> [[TMP0]], [[X]]
+; CHECK-NEXT: [[TMP1:%.*]] = and <2 x i8> [[X:%.*]], <i8 -4, i8 -1>
+; CHECK-NEXT: [[RET:%.*]] = icmp ne <2 x i8> [[TMP1]], zeroinitializer
; CHECK-NEXT: ret <2 x i1> [[RET]]
;
%tmp0 = and <2 x i8> %x, <i8 3, i8 0>
@@ -189,8 +189,8 @@ define i1 @oneuse0(i8 %x) {
define i1 @n0(i8 %x) {
; CHECK-LABEL: @n0(
-; CHECK-NEXT: [[TMP0:%.*]] = and i8 [[X:%.*]], 4
-; CHECK-NEXT: [[RET:%.*]] = icmp ne i8 [[TMP0]], [[X]]
+; CHECK-NEXT: [[TMP1:%.*]] = and i8 [[X:%.*]], -5
+; CHECK-NEXT: [[RET:%.*]] = icmp ne i8 [[TMP1]], 0
; CHECK-NEXT: ret i1 [[RET]]
;
%tmp0 = and i8 %x, 4 ; power-of-two, but invalid.
@@ -211,8 +211,8 @@ define i1 @n1(i8 %x, i8 %y, i8 %notx) {
define <2 x i1> @n2(<2 x i8> %x) {
; CHECK-LABEL: @n2(
-; CHECK-NEXT: [[TMP0:%.*]] = and <2 x i8> [[X:%.*]], <i8 3, i8 16>
-; CHECK-NEXT: [[RET:%.*]] = icmp ne <2 x i8> [[TMP0]], [[X]]
+; CHECK-NEXT: [[TMP1:%.*]] = and <2 x i8> [[X:%.*]], <i8 -4, i8 -17>
+; CHECK-NEXT: [[RET:%.*]] = icmp ne <2 x i8> [[TMP1]], zeroinitializer
; CHECK-NEXT: ret <2 x i1> [[RET]]
;
%tmp0 = and <2 x i8> %x, <i8 3, i8 16> ; only the first one is valid.
diff --git a/llvm/test/Transforms/InstCombine/icmp-logical.ll b/llvm/test/Transforms/InstCombine/icmp-logical.ll
index ccd86f1a6739ae..4690ead483a5ba 100644
--- a/llvm/test/Transforms/InstCombine/icmp-logical.ll
+++ b/llvm/test/Transforms/InstCombine/icmp-logical.ll
@@ -129,8 +129,8 @@ define i1 @masked_or_allones_logical(i32 %A) {
define i1 @masked_and_notA(i32 %A) {
; CHECK-LABEL: @masked_and_notA(
-; CHECK-NEXT: [[MASK2:%.*]] = and i32 [[A:%.*]], 78
-; CHECK-NEXT: [[TST2:%.*]] = icmp ne i32 [[MASK2]], [[A]]
+; CHECK-NEXT: [[TMP1:%.*]] = and i32 [[A:%.*]], -79
+; CHECK-NEXT: [[TST2:%.*]] = icmp ne i32 [[TMP1]], 0
; CHECK-NEXT: ret i1 [[TST2]]
;
%mask1 = and i32 %A, 14
@@ -143,8 +143,8 @@ define i1 @masked_and_notA(i32 %A) {
define i1 @masked_and_notA_logical(i32 %A) {
; CHECK-LABEL: @masked_and_notA_logical(
-; CHECK-NEXT: [[MASK2:%.*]] = and i32 [[A:%.*]], 78
-; CHECK-NEXT: [[TST2:%.*]] = icmp ne i32 [[MASK2]], [[A]]
+; CHECK-NEXT: [[TMP1:%.*]] = and i32 [[A:%.*]], -79
+; CHECK-NEXT: [[TST2:%.*]] = icmp ne i32 [[TMP1]], 0
; CHECK-NEXT: ret i1 [[TST2]]
;
%mask1 = and i32 %A, 14
@@ -157,11 +157,9 @@ define i1 @masked_and_notA_logical(i32 %A) {
define i1 @masked_and_notA_slightly_optimized(i32 %A) {
; CHECK-LABEL: @masked_and_notA_slightly_optimized(
-; CHECK-NEXT: [[T0:%.*]] = icmp ugt i32 [[A:%.*]], 7
-; CHECK-NEXT: [[MASK2:%.*]] = and i32 [[A]], 39
-; CHECK-NEXT: [[TST2:%.*]] = icmp ne i32 [[MASK2]], [[A]]
-; CHECK-NEXT: [[RES:%.*]] = and i1 [[T0]], [[TST2]]
-; CHECK-NEXT: ret i1 [[RES]]
+; CHECK-NEXT: [[TMP1:%.*]] = and i32 [[A:%.*]], -40
+; CHECK-NEXT: [[TST2:%.*]] = icmp ne i32 [[TMP1]], 0
+; CHECK-NEXT: ret i1 [[TST2]]
;
%t0 = icmp uge i32 %A, 8
%mask2 = and i32 %A, 39
@@ -172,11 +170,9 @@ define i1 @masked_and_notA_slightly_optimized(i32 %A) {
define i1 @masked_and_notA_slightly_optimized_logical(i32 %A) {
; CHECK-LABEL: @masked_and_notA_slightly_optimized_logical(
-; CHECK-NEXT: [[T0:%.*]] = icmp ugt i32 [[A:%.*]], 7
-; CHECK-NEXT: [[MASK2:%.*]] = and i32 [[A]], 39
-; CHECK-NEXT: [[TST2:%.*]] = icmp ne i32 [[MASK2]], [[A]]
-; CHECK-NEXT: [[RES:%.*]] = and i1 [[T0]], [[TST2]]
-; CHECK-NEXT: ret i1 [[RES]]
+; CHECK-NEXT: [[TMP1:%.*]] = and i32 [[A:%.*]], -40
+; CHECK-NEXT: [[TST2:%.*]] = icmp ne i32 [[TMP1]], 0
+; CHECK-NEXT: ret i1 [[TST2]]
;
%t0 = icmp uge i32 %A, 8
%mask2 = and i32 %A, 39
@@ -187,8 +183,8 @@ define i1 @masked_and_notA_slightly_optimized_logical(i32 %A) {
define i1 @masked_or_A(i32 %A) {
; CHECK-LABEL: @masked_or_A(
-; CHECK-NEXT: [[MASK2:%.*]] = and i32 [[A:%.*]], 78
-; CHECK-NEXT: [[TST2:%.*]] = icmp eq i32 [[MASK2]], [[A]]
+; CHECK-NEXT: [[TMP1:%.*]] = and i32 [[A:%.*]], -79
+; CHECK-NEXT: [[TST2:%.*]] = icmp eq i32 [[TMP1]], 0
; CHECK-NEXT: ret i1 [[TST2]]
;
%mask1 = and i32 %A, 14
@@ -201,8 +197,8 @@ define i1 @masked_or_A(i32 %A) {
define i1 @masked_or_A_logical(i32 %A) {
; CHECK-LABEL: @masked_or_A_logical(
-; CHECK-NEXT: [[MASK2:%.*]] = and i32 [[A:%.*]], 78
-; CHECK-NEXT: [[TST2:%.*]] = icmp eq i32 [[MASK2]], [[A]]
+; CHECK-NEXT: [[TMP1:%.*]] = and i32 [[A:%.*]], -79
+; CHECK-NEXT: [[TST2:%.*]] = icmp eq i32 [[TMP1]], 0
; CHECK-NEXT: ret i1 [[TST2]]
;
%mask1 = and i32 %A, 14
@@ -215,11 +211,9 @@ define i1 @masked_or_A_logical(i32 %A) {
define i1 @masked_or_A_slightly_optimized(i32 %A) {
; CHECK-LABEL: @masked_or_A_slightly_optimized(
-; CHECK-NEXT: [[T0:%.*]] = icmp ult i32 [[A:%.*]], 8
-; CHECK-NEXT: [[MASK2:%.*]] = and i32 [[A]], 39
-; CHECK-NEXT: [[TST2:%.*]] = icmp eq i32 [[MASK2]], [[A]]
-; CHECK-NEXT: [[RES:%.*]] = or i1 [[T0]], [[TST2]]
-; CHECK-NEXT: ret i1 [[RES]]
+; CHECK-NEXT: [[TMP1:%.*]] = and i32 [[A:%.*]], -40
+; CHECK-NEXT: [[TST2:%.*]] = icmp eq i32 [[TMP1]], 0
+; CHECK-NEXT: ret i1 [[TST2]]
;
%t0 = icmp ult i32 %A, 8
%mask2 = and i32 %A, 39
@@ -230,11 +224,9 @@ define i1 @masked_or_A_slightly_optimized(i32 %A) {
define i1 @masked_or_A_slightly_optimized_logical(i32 %A) {
; CHECK-LABEL: @masked_or_A_slightly_optimized_logical(
-; CHECK-NEXT: [[T0:%.*]] = icmp ult i32 [[A:%.*]], 8
-; CHECK-NEXT: [[MASK2:%.*]] = and i32 [[A]], 39
-; CHECK-NEXT: [[TST2:%.*]] = icmp eq i32 [[MASK2]], [[A]]
-; CHECK-NEXT: [[RES:%.*]] = or i1 [[T0]], [[TST2]]
-; CHECK-NEXT: ret i1 [[RES]]
+; CHECK-NEXT: [[TMP1:%.*]] = and i32 [[A:%.*]], -40
+; CHECK-NEXT: [[TST2:%.*]] = icmp eq i32 [[TMP1]], 0
+; CHECK-NEXT: ret i1 [[TST2]]
;
%t0 = icmp ult i32 %A, 8
%mask2 = and i32 %A, 39
diff --git a/llvm/test/Transforms/InstCombine/select.ll b/llvm/test/Transforms/InstCombine/select.ll
index 39aeaa577fa5c5..e91c468fb67841 100644
--- a/llvm/test/Transforms/InstCombine/select.ll
+++ b/llvm/test/Transforms/InstCombine/select.ll
@@ -846,8 +846,8 @@ define i32 @test52(i32 %n, i32 %m) {
define i32 @test53(i32 %x) {
; CHECK-LABEL: @test53(
-; CHECK-NEXT: [[AND:%.*]] = and i32 [[X:%.*]], 2
-; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[AND]], [[X]]
+; CHECK-NEXT: [[TMP1:%.*]] = and i32 [[X:%.*]], -3
+; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[TMP1]], 0
; CHECK-NEXT: [[SEL:%.*]] = select i1 [[CMP]], i32 2, i32 1
; CHECK-NEXT: ret i32 [[SEL]]
;
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