[llvm] [InstCombine] Simplifiy `(-x * y * -x)` into `(x * y * x)` (PR #72953)
via llvm-commits
llvm-commits at lists.llvm.org
Thu Dec 21 01:49:14 PST 2023
https://github.com/Z572 updated https://github.com/llvm/llvm-project/pull/72953
>From 1afa7534fcf4f72a0b42cc892f982d277058bdce Mon Sep 17 00:00:00 2001
From: Zheng Junjie <zhengjunjie at iscas.ac.cn>
Date: Tue, 21 Nov 2023 11:41:20 +0800
Subject: [PATCH] [InstCombine] Simplifiy `(-X * Y) * -X` into `(X * Y) * X`.
and `(-X << Y) * -X` into `(X << Y) * X`
proof: https://alive2.llvm.org/ce/z/HsrmTC
---
.../InstCombine/InstCombineMulDivRem.cpp | 7 +
.../InstCombine/mul-inseltpoison.ll | 5 +-
llvm/test/Transforms/InstCombine/mul.ll | 173 ++++++++++++++++++
3 files changed, 182 insertions(+), 3 deletions(-)
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
index 40156726c7038b..f8808b61a16663 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
@@ -352,6 +352,13 @@ Instruction *InstCombinerImpl::visitMul(BinaryOperator &I) {
if (match(&I, m_c_Mul(m_OneUse(m_Neg(m_Value(X))), m_Value(Y))))
return BinaryOperator::CreateNeg(Builder.CreateMul(X, Y));
+ // (-X * Y) * -X --> (X * Y) * X
+ // (-X << Y) * -X --> (X << Y) * X
+ if (match(Op1, m_Neg(m_Value(X)))) {
+ if (Value *NegOp0 = Negator::Negate(false, /*IsNSW*/ false, Op0, *this))
+ return BinaryOperator::CreateMul(NegOp0, X);
+ }
+
// (X / Y) * Y = X - (X % Y)
// (X / Y) * -Y = (X % Y) - X
{
diff --git a/llvm/test/Transforms/InstCombine/mul-inseltpoison.ll b/llvm/test/Transforms/InstCombine/mul-inseltpoison.ll
index 448558d755a576..8fe4261bbf009c 100644
--- a/llvm/test/Transforms/InstCombine/mul-inseltpoison.ll
+++ b/llvm/test/Transforms/InstCombine/mul-inseltpoison.ll
@@ -672,9 +672,8 @@ define <2 x i32> @test_mul_canonicalize_vec(<2 x i32> %x, <2 x i32> %y) {
define i32 @test_mul_canonicalize_multiple_uses(i32 %x, i32 %y) {
; CHECK-LABEL: @test_mul_canonicalize_multiple_uses(
-; CHECK-NEXT: [[NEG:%.*]] = sub i32 0, [[X:%.*]]
-; CHECK-NEXT: [[MUL:%.*]] = mul i32 [[NEG]], [[Y:%.*]]
-; CHECK-NEXT: [[MUL2:%.*]] = mul i32 [[MUL]], [[NEG]]
+; CHECK-NEXT: [[MUL_NEG:%.*]] = mul i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT: [[MUL2:%.*]] = mul i32 [[MUL_NEG]], [[X]]
; CHECK-NEXT: ret i32 [[MUL2]]
;
%neg = sub i32 0, %x
diff --git a/llvm/test/Transforms/InstCombine/mul.ll b/llvm/test/Transforms/InstCombine/mul.ll
index 42698b5102bc5b..21f08b0f291396 100644
--- a/llvm/test/Transforms/InstCombine/mul.ll
+++ b/llvm/test/Transforms/InstCombine/mul.ll
@@ -1233,17 +1233,190 @@ define <2 x i32> @test_mul_canonicalize_vec(<2 x i32> %x, <2 x i32> %y) {
define i32 @test_mul_canonicalize_multiple_uses(i32 %x, i32 %y) {
; CHECK-LABEL: @test_mul_canonicalize_multiple_uses(
+; CHECK-NEXT: [[MUL_NEG:%.*]] = mul i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT: [[MUL2:%.*]] = mul i32 [[MUL_NEG]], [[X]]
+; CHECK-NEXT: ret i32 [[MUL2]]
+;
+ %neg = sub i32 0, %x
+ %mul = mul i32 %neg, %y
+ %mul2 = mul i32 %mul, %neg
+ ret i32 %mul2
+}
+
+define i32 @mul_nsw_mul_nsw_neg(i32 %x, i32 %y) {
+; CHECK-LABEL: @mul_nsw_mul_nsw_neg(
+; CHECK-NEXT: [[MUL_NEG:%.*]] = mul i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT: [[MUL2:%.*]] = mul i32 [[MUL_NEG]], [[X]]
+; CHECK-NEXT: ret i32 [[MUL2]]
+;
+ %neg = sub i32 0, %x
+ %mul = mul nsw i32 %neg, %y
+ %mul2 = mul nsw i32 %mul, %neg
+ ret i32 %mul2
+}
+
+define i32 @mul_mul_nsw_neg(i32 %x,i32 %y) {
+; CHECK-LABEL: @mul_mul_nsw_neg(
+; CHECK-NEXT: [[MUL_NEG:%.*]] = mul i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT: [[MUL2:%.*]] = mul i32 [[MUL_NEG]], [[X]]
+; CHECK-NEXT: ret i32 [[MUL2]]
+;
+ %neg = sub i32 0, %x
+ %mul = mul nsw i32 %neg, %y
+ %mul2 = mul i32 %mul, %neg
+ ret i32 %mul2
+}
+
+define i32 @mul_nsw_mul_neg(i32 %x,i32 %y) {
+; CHECK-LABEL: @mul_nsw_mul_neg(
+; CHECK-NEXT: [[MUL_NEG:%.*]] = mul i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT: [[MUL2:%.*]] = mul i32 [[MUL_NEG]], [[X]]
+; CHECK-NEXT: ret i32 [[MUL2]]
+;
+ %neg = sub i32 0, %x
+ %mul = mul i32 %neg, %y
+ %mul2 = mul nsw i32 %mul, %neg
+ ret i32 %mul2
+}
+
+define i32 @mul_nsw_mul_neg_onearg(i32 %x) {
+; CHECK-LABEL: @mul_nsw_mul_neg_onearg(
+; CHECK-NEXT: [[MUL_NEG:%.*]] = mul i32 [[X:%.*]], [[X]]
+; CHECK-NEXT: [[MUL2:%.*]] = mul i32 [[MUL_NEG]], [[X]]
+; CHECK-NEXT: ret i32 [[MUL2]]
+;
+ %neg = sub i32 0, %x
+ %mul = mul i32 %neg, %x
+ %mul2 = mul nsw i32 %mul, %neg
+ ret i32 %mul2
+}
+
+define i8 @mul_mul_nsw_neg_onearg(i8 %x) {
+; CHECK-LABEL: @mul_mul_nsw_neg_onearg(
+; CHECK-NEXT: [[MUL_NEG:%.*]] = mul i8 [[X:%.*]], [[X]]
+; CHECK-NEXT: [[MUL2:%.*]] = mul i8 [[MUL_NEG]], [[X]]
+; CHECK-NEXT: ret i8 [[MUL2]]
+;
+ %neg = sub i8 0, %x
+ %mul = mul nsw i8 %neg, %x
+ %mul2 = mul i8 %mul, %neg
+ ret i8 %mul2
+}
+
+define i32 @mul_nsw_mul_nsw_neg_onearg(i32 %x) {
+; CHECK-LABEL: @mul_nsw_mul_nsw_neg_onearg(
+; CHECK-NEXT: [[MUL_NEG:%.*]] = mul i32 [[X:%.*]], [[X]]
+; CHECK-NEXT: [[MUL2:%.*]] = mul i32 [[MUL_NEG]], [[X]]
+; CHECK-NEXT: ret i32 [[MUL2]]
+;
+ %neg = sub i32 0, %x
+ %mul = mul nsw i32 %neg, %x
+ %mul2 = mul nsw i32 %mul, %neg
+ ret i32 %mul2
+}
+
+define i32 @mul_nsw_shl_nsw_neg(i32 %x, i32 %y) {
+; CHECK-LABEL: @mul_nsw_shl_nsw_neg(
+; CHECK-NEXT: [[SHL_NEG:%.*]] = shl i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT: [[MUL:%.*]] = mul i32 [[SHL_NEG]], [[X]]
+; CHECK-NEXT: ret i32 [[MUL]]
+;
+ %neg = sub i32 0, %x
+ %shl = shl nsw i32 %neg, %y
+ %mul = mul nsw i32 %shl, %neg
+ ret i32 %mul
+}
+
+define i32 @mul_shl_nsw_neg(i32 %x,i32 %y) {
+; CHECK-LABEL: @mul_shl_nsw_neg(
+; CHECK-NEXT: [[SHL_NEG:%.*]] = shl i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT: [[MUL:%.*]] = mul i32 [[SHL_NEG]], [[X]]
+; CHECK-NEXT: ret i32 [[MUL]]
+;
+ %neg = sub i32 0, %x
+ %shl = shl nsw i32 %neg, %y
+ %mul = mul i32 %shl, %neg
+ ret i32 %mul
+}
+
+define i32 @mul_nsw_shl_neg(i32 %x,i32 %y) {
+; CHECK-LABEL: @mul_nsw_shl_neg(
+; CHECK-NEXT: [[SHL_NEG:%.*]] = shl i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT: [[MUL:%.*]] = mul i32 [[SHL_NEG]], [[X]]
+; CHECK-NEXT: ret i32 [[MUL]]
+;
+ %neg = sub i32 0, %x
+ %shl = shl i32 %neg, %y
+ %mul = mul nsw i32 %shl, %neg
+ ret i32 %mul
+}
+
+define i32 @mul_nsw_shl_neg_onearg(i32 %x) {
+; CHECK-LABEL: @mul_nsw_shl_neg_onearg(
+; CHECK-NEXT: [[SHL_NEG:%.*]] = shl i32 [[X:%.*]], [[X]]
+; CHECK-NEXT: [[MUL:%.*]] = mul i32 [[SHL_NEG]], [[X]]
+; CHECK-NEXT: ret i32 [[MUL]]
+;
+ %neg = sub i32 0, %x
+ %shl = shl i32 %neg, %x
+ %mul = mul nsw i32 %shl, %neg
+ ret i32 %mul
+}
+
+define i8 @mul_shl_nsw_neg_onearg(i8 %x) {
+; CHECK-LABEL: @mul_shl_nsw_neg_onearg(
+; CHECK-NEXT: [[SHL_NEG:%.*]] = shl i8 [[X:%.*]], [[X]]
+; CHECK-NEXT: [[MUL:%.*]] = mul i8 [[SHL_NEG]], [[X]]
+; CHECK-NEXT: ret i8 [[MUL]]
+;
+ %neg = sub i8 0, %x
+ %shl = shl nsw i8 %neg, %x
+ %mul = mul i8 %shl, %neg
+ ret i8 %mul
+}
+
+define i32 @mul_nsw_shl_nsw_neg_onearg(i32 %x) {
+; CHECK-LABEL: @mul_nsw_shl_nsw_neg_onearg(
+; CHECK-NEXT: [[SHL_NEG:%.*]] = mul i32 [[X:%.*]], [[X]]
+; CHECK-NEXT: [[MUL:%.*]] = mul i32 [[SHL_NEG]], [[X]]
+; CHECK-NEXT: ret i32 [[MUL]]
+;
+ %neg = sub i32 0, %x
+ %shl = mul nsw i32 %neg, %x
+ %mul = mul nsw i32 %shl, %neg
+ ret i32 %mul
+}
+
+define i32 @mul_use_mul_neg(i32 %x,i32 %y) {
+; CHECK-LABEL: @mul_use_mul_neg(
; CHECK-NEXT: [[NEG:%.*]] = sub i32 0, [[X:%.*]]
; CHECK-NEXT: [[MUL:%.*]] = mul i32 [[NEG]], [[Y:%.*]]
+; CHECK-NEXT: call void @use32(i32 [[MUL]])
; CHECK-NEXT: [[MUL2:%.*]] = mul i32 [[MUL]], [[NEG]]
; CHECK-NEXT: ret i32 [[MUL2]]
;
%neg = sub i32 0, %x
%mul = mul i32 %neg, %y
+ call void @use32(i32 %mul)
%mul2 = mul i32 %mul, %neg
ret i32 %mul2
}
+define i32 @mul_shl_use_mul_neg(i32 %x,i32 %y) {
+; CHECK-LABEL: @mul_shl_use_mul_neg(
+; CHECK-NEXT: [[NEG:%.*]] = sub i32 0, [[X:%.*]]
+; CHECK-NEXT: [[SHL:%.*]] = shl i32 [[NEG]], [[Y:%.*]]
+; CHECK-NEXT: call void @use32(i32 [[SHL]])
+; CHECK-NEXT: [[MUL2:%.*]] = mul i32 [[SHL]], [[NEG]]
+; CHECK-NEXT: ret i32 [[MUL2]]
+;
+ %neg = sub i32 0, %x
+ %shl = shl i32 %neg, %y
+ call void @use32(i32 %shl)
+ %mul2 = mul i32 %shl, %neg
+ ret i32 %mul2
+}
+
@X = global i32 5
define i64 @test_mul_canonicalize_neg_is_not_undone(i64 %L1) {
More information about the llvm-commits
mailing list