[llvm] 119194a - [InstCombine] Transform `(icmp ult/uge (and X, Y), X)` -> `(icmp ne/eq (and X, Y), X)`
Noah Goldstein via llvm-commits
llvm-commits at lists.llvm.org
Wed Sep 13 13:50:42 PDT 2023
Author: Noah Goldstein
Date: 2023-09-13T15:50:17-05:00
New Revision: 119194ada6385f0a75a7e7e50915daab2841dc9f
URL: https://github.com/llvm/llvm-project/commit/119194ada6385f0a75a7e7e50915daab2841dc9f
DIFF: https://github.com/llvm/llvm-project/commit/119194ada6385f0a75a7e7e50915daab2841dc9f.diff
LOG: [InstCombine] Transform `(icmp ult/uge (and X, Y), X)` -> `(icmp ne/eq (and X, Y), X)`
eq/ne are generally easier to reason about elsewhere.
ult -> ne: https://alive2.llvm.org/ce/z/5wxXGt
uge -> eq: https://alive2.llvm.org/ce/z/Dw6kqG
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D145425
Added:
Modified:
llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-uge-to-icmp-ule.ll
llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-ugt-to-icmp-ugt.ll
llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-ule-to-icmp-ule.ll
llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-ult-to-icmp-ugt.ll
llvm/test/Transforms/InstCombine/icmp-of-and-x.ll
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
index 7436bf2793ae722..56a542479a24d5a 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -4427,6 +4427,30 @@ static Instruction *foldICmpXNegX(ICmpInst &I,
return nullptr;
}
+static Instruction *foldICmpAndXX(ICmpInst &I, const SimplifyQuery &Q,
+ InstCombinerImpl &IC) {
+ Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1), *A;
+ // Normalize and operand as operand 0.
+ CmpInst::Predicate Pred = I.getPredicate();
+ if (match(Op1, m_c_And(m_Specific(Op0), m_Value()))) {
+ std::swap(Op0, Op1);
+ Pred = ICmpInst::getSwappedPredicate(Pred);
+ }
+
+ if (!match(Op0, m_c_And(m_Specific(Op1), m_Value(A))))
+ return nullptr;
+
+ // (icmp (X & Y) u< X --> (X & Y) != X
+ if (Pred == ICmpInst::ICMP_ULT)
+ return new ICmpInst(ICmpInst::ICMP_NE, Op0, Op1);
+
+ // (icmp (X & Y) u>= X --> (X & Y) == X
+ if (Pred == ICmpInst::ICMP_UGE)
+ return new ICmpInst(ICmpInst::ICMP_EQ, Op0, Op1);
+
+ return nullptr;
+}
+
static Instruction *foldICmpOrXX(ICmpInst &I, const SimplifyQuery &Q,
InstCombinerImpl &IC) {
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1), *A;
@@ -4956,6 +4980,9 @@ Instruction *InstCombinerImpl::foldICmpBinOp(ICmpInst &I,
if (Value *V = foldICmpWithLowBitMaskedVal(I, Builder))
return replaceInstUsesWith(I, V);
+ if (Instruction *R = foldICmpAndXX(I, Q, *this))
+ return R;
+
if (Value *V = foldICmpWithTruncSignExtendedVal(I, Builder))
return replaceInstUsesWith(I, V);
diff --git a/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-uge-to-icmp-ule.ll b/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-uge-to-icmp-ule.ll
index c84b8f8024bf4c9..ff09e255185b5ad 100644
--- a/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-uge-to-icmp-ule.ll
+++ b/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-uge-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 uge <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>
@@ -175,8 +175,8 @@ define i1 @oneuse0(i8 %x) {
define i1 @n0(i8 %x) {
; CHECK-LABEL: @n0(
-; CHECK-NEXT: [[TMP0:%.*]] = and i8 [[X:%.*]], 4
-; CHECK-NEXT: [[RET:%.*]] = icmp uge 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.
@@ -197,8 +197,8 @@ 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 uge <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-ugt-to-icmp-ugt.ll b/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-ugt-to-icmp-ugt.ll
index 69f5cf719740c15..4ad04710fd7bb96 100644
--- a/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-ugt-to-icmp-ugt.ll
+++ b/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-ugt-to-icmp-ugt.ll
@@ -75,8 +75,8 @@ define <2 x i1> @p2_vec_nonsplat() {
define <2 x i1> @p2_vec_nonsplat_edgecase0() {
; CHECK-LABEL: @p2_vec_nonsplat_edgecase0(
; CHECK-NEXT: [[X:%.*]] = call <2 x i8> @gen2x8()
-; CHECK-NEXT: [[TMP0:%.*]] = and <2 x i8> [[X]], <i8 3, i8 0>
-; CHECK-NEXT: [[RET:%.*]] = icmp ugt <2 x i8> [[X]], [[TMP0]]
+; 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]]
;
%x = call <2 x i8> @gen2x8()
@@ -201,8 +201,8 @@ define i1 @oneuse0() {
define i1 @n0() {
; CHECK-LABEL: @n0(
; CHECK-NEXT: [[X:%.*]] = call i8 @gen8()
-; CHECK-NEXT: [[TMP0:%.*]] = and i8 [[X]], 4
-; CHECK-NEXT: [[RET:%.*]] = icmp ugt i8 [[X]], [[TMP0]]
+; CHECK-NEXT: [[TMP1:%.*]] = and i8 [[X]], -5
+; CHECK-NEXT: [[RET:%.*]] = icmp ne i8 [[TMP1]], 0
; CHECK-NEXT: ret i1 [[RET]]
;
%x = call i8 @gen8()
@@ -227,8 +227,8 @@ define i1 @n1(i8 %y, i8 %notx) {
define <2 x i1> @n2() {
; CHECK-LABEL: @n2(
; CHECK-NEXT: [[X:%.*]] = call <2 x i8> @gen2x8()
-; CHECK-NEXT: [[TMP0:%.*]] = and <2 x i8> [[X]], <i8 3, i8 16>
-; CHECK-NEXT: [[RET:%.*]] = icmp ugt <2 x i8> [[X]], [[TMP0]]
+; 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]]
;
%x = call <2 x i8> @gen2x8()
diff --git a/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-ule-to-icmp-ule.ll b/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-ule-to-icmp-ule.ll
index bd8ed8ef4c36a5a..8e513dcbf4ef3a3 100644
--- a/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-ule-to-icmp-ule.ll
+++ b/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-ule-to-icmp-ule.ll
@@ -75,8 +75,8 @@ define <2 x i1> @p2_vec_nonsplat() {
define <2 x i1> @p2_vec_nonsplat_edgecase0() {
; CHECK-LABEL: @p2_vec_nonsplat_edgecase0(
; CHECK-NEXT: [[X:%.*]] = call <2 x i8> @gen2x8()
-; CHECK-NEXT: [[TMP0:%.*]] = and <2 x i8> [[X]], <i8 3, i8 0>
-; CHECK-NEXT: [[RET:%.*]] = icmp ule <2 x i8> [[X]], [[TMP0]]
+; 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]]
;
%x = call <2 x i8> @gen2x8()
@@ -189,8 +189,8 @@ define i1 @oneuse0() {
define i1 @n0() {
; CHECK-LABEL: @n0(
; CHECK-NEXT: [[X:%.*]] = call i8 @gen8()
-; CHECK-NEXT: [[TMP0:%.*]] = and i8 [[X]], 4
-; CHECK-NEXT: [[RET:%.*]] = icmp ule i8 [[X]], [[TMP0]]
+; CHECK-NEXT: [[TMP1:%.*]] = and i8 [[X]], -5
+; CHECK-NEXT: [[RET:%.*]] = icmp eq i8 [[TMP1]], 0
; CHECK-NEXT: ret i1 [[RET]]
;
%x = call i8 @gen8()
@@ -215,8 +215,8 @@ define i1 @n1(i8 %y, i8 %notx) {
define <2 x i1> @n2() {
; CHECK-LABEL: @n2(
; CHECK-NEXT: [[X:%.*]] = call <2 x i8> @gen2x8()
-; CHECK-NEXT: [[TMP0:%.*]] = and <2 x i8> [[X]], <i8 3, i8 16>
-; CHECK-NEXT: [[RET:%.*]] = icmp ule <2 x i8> [[X]], [[TMP0]]
+; 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]]
;
%x = call <2 x i8> @gen2x8()
diff --git a/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-ult-to-icmp-ugt.ll b/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-ult-to-icmp-ugt.ll
index a7e58cbb617ea57..d02ecf6965e878f 100644
--- a/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-ult-to-icmp-ugt.ll
+++ b/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-ult-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 ult <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>
@@ -186,8 +186,8 @@ define i1 @oneuse0(i8 %x) {
define i1 @n0(i8 %x) {
; CHECK-LABEL: @n0(
-; CHECK-NEXT: [[TMP0:%.*]] = and i8 [[X:%.*]], 4
-; CHECK-NEXT: [[RET:%.*]] = icmp ult 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.
@@ -208,8 +208,8 @@ 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 ult <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-of-and-x.ll b/llvm/test/Transforms/InstCombine/icmp-of-and-x.ll
index 3d4ae70932028ac..e95c72b75f97dfd 100644
--- a/llvm/test/Transforms/InstCombine/icmp-of-and-x.ll
+++ b/llvm/test/Transforms/InstCombine/icmp-of-and-x.ll
@@ -7,7 +7,7 @@ declare void @llvm.assume(i1)
define i1 @icmp_ult_x_y(i8 %x, i8 %y) {
; CHECK-LABEL: @icmp_ult_x_y(
; CHECK-NEXT: [[AND:%.*]] = and i8 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT: [[Z:%.*]] = icmp ult i8 [[AND]], [[X]]
+; CHECK-NEXT: [[Z:%.*]] = icmp ne i8 [[AND]], [[X]]
; CHECK-NEXT: ret i1 [[Z]]
;
%and = and i8 %x, %y
@@ -19,7 +19,7 @@ define i1 @icmp_ult_x_y_2(i8 %xx, i8 %y) {
; CHECK-LABEL: @icmp_ult_x_y_2(
; CHECK-NEXT: [[X:%.*]] = mul i8 [[XX:%.*]], [[XX]]
; CHECK-NEXT: [[AND:%.*]] = and i8 [[X]], [[Y:%.*]]
-; CHECK-NEXT: [[Z:%.*]] = icmp ugt i8 [[X]], [[AND]]
+; CHECK-NEXT: [[Z:%.*]] = icmp ne i8 [[AND]], [[X]]
; CHECK-NEXT: ret i1 [[Z]]
;
%x = mul i8 %xx, %xx
@@ -31,7 +31,7 @@ define i1 @icmp_ult_x_y_2(i8 %xx, i8 %y) {
define <2 x i1> @icmp_uge_x_y(<2 x i8> %x, <2 x i8> %y) {
; CHECK-LABEL: @icmp_uge_x_y(
; CHECK-NEXT: [[AND:%.*]] = and <2 x i8> [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT: [[Z:%.*]] = icmp uge <2 x i8> [[AND]], [[X]]
+; CHECK-NEXT: [[Z:%.*]] = icmp eq <2 x i8> [[AND]], [[X]]
; CHECK-NEXT: ret <2 x i1> [[Z]]
;
%and = and <2 x i8> %x, %y
@@ -43,7 +43,7 @@ define i1 @icmp_uge_x_y_2(i8 %xx, i8 %y) {
; CHECK-LABEL: @icmp_uge_x_y_2(
; CHECK-NEXT: [[X:%.*]] = mul i8 [[XX:%.*]], [[XX]]
; CHECK-NEXT: [[AND:%.*]] = and i8 [[X]], [[Y:%.*]]
-; CHECK-NEXT: [[Z:%.*]] = icmp ule i8 [[X]], [[AND]]
+; CHECK-NEXT: [[Z:%.*]] = icmp eq i8 [[AND]], [[X]]
; CHECK-NEXT: ret i1 [[Z]]
;
%x = mul i8 %xx, %xx
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