[PATCH] D126040: [InstCombine] Fold a mul with bool value into and
Allen zhong via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Thu May 19 21:25:36 PDT 2022
Allen updated this revision to Diff 430875.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D126040/new/
https://reviews.llvm.org/D126040
Files:
llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
llvm/test/Transforms/InstCombine/trunc.ll
Index: llvm/test/Transforms/InstCombine/trunc.ll
===================================================================
--- llvm/test/Transforms/InstCombine/trunc.ll
+++ llvm/test/Transforms/InstCombine/trunc.ll
@@ -1021,3 +1021,25 @@
%sub = add nsw i16 %cast, -1
ret i16 %sub
}
+
+define i64 @PR55599_One(i64 %x, i64 %y) {
+; CHECK-LABEL: @PR55599_One(
+; CHECK-NEXT: [[AND2:%.*]] = and i64 [[Y:%.*]], 1
+; CHECK-NEXT: [[MUL:%.*]] = and i64 [[AND2]], [[X:%.*]]
+; CHECK-NEXT: ret i64 [[MUL]]
+;
+ %and1 = and i64 %x, 1
+ %and2 = and i64 %y, 1
+ %mul = mul i64 %and1, %and2
+ ret i64 %mul
+}
+
+define i64 @PR55599_Zero(i64 %x, i64 %y, i64 %c) {
+; CHECK-LABEL: @PR55599_Zero(
+; CHECK-NEXT: ret i64 0
+;
+ %and1 = and i64 %x, %c
+ %and2 = and i64 %y, 0
+ %mul = mul i64 %and1, %and2
+ ret i64 %mul
+}
Index: llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
+++ llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
@@ -305,6 +305,15 @@
if (I.getType()->isIntOrIntVectorTy(1))
return BinaryOperator::CreateAnd(Op0, Op1);
+ // X * Y --> X & Y, iff X, Y can be only 0 or 1
+ {
+ if (match(Op0, m_And(m_Value(X), m_One())) &&
+ match(Op1, m_And(m_Value(Y), m_One())) &&
+ match(Op0, m_And(m_Value(X), m_Zero())) &&
+ match(Op1, m_And(m_Value(X), m_Zero())))
+ return BinaryOperator::CreateAnd(Op0, Op1);
+ }
+
// X*(1 << Y) --> X << Y
// (1 << Y)*X --> X << Y
{
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