[llvm] 42c94bc - [InstCombine] allow vector splat matching for bitwise logic fold
Sanjay Patel via llvm-commits
llvm-commits at lists.llvm.org
Mon Nov 1 08:45:49 PDT 2021
Author: Sanjay Patel
Date: 2021-11-01T11:39:48-04:00
New Revision: 42c94bc1abd1029c35846fd500a8b2bb008fef73
URL: https://github.com/llvm/llvm-project/commit/42c94bc1abd1029c35846fd500a8b2bb008fef73
DIFF: https://github.com/llvm/llvm-project/commit/42c94bc1abd1029c35846fd500a8b2bb008fef73.diff
LOG: [InstCombine] allow vector splat matching for bitwise logic fold
Similar to 54e969cffddb (and with cosmetic updates to hopefully
make that easier to read), this fold has been around since early
in LLVM history.
Intermediate folds have been added subsequently, so extra uses
are required to exercise this code.
The test example actually shows an unintended consequence with
extra uses - we end up with an extra instruction compared to what
we started with. But this at least makes scalar/vector consistent.
General proof:
https://alive2.llvm.org/ce/z/tmuBza
Added:
Modified:
llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
llvm/test/Transforms/InstCombine/and-or.ll
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index aa60b0fa58cc..3c51551ffef6 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -2704,58 +2704,50 @@ Instruction *InstCombinerImpl::visitOr(BinaryOperator &I) {
if (match(Op0, m_And(m_Value(A), m_Value(C))) &&
match(Op1, m_And(m_Value(B), m_Value(D)))) {
- // (A & MaskC0) | (B & MaskC1)
- const APInt *MaskC0, *MaskC1;
- if (match(C, m_APInt(MaskC0)) && match(D, m_APInt(MaskC1))) {
+ // (A & C0) | (B & C1)
+ const APInt *C0, *C1;
+ if (match(C, m_APInt(C0)) && match(D, m_APInt(C1))) {
Value *X;
- if (*MaskC0 == ~*MaskC1) {
+ if (*C0 == ~*C1) {
// ((X | B) & MaskC) | (B & ~MaskC) -> (X & MaskC) | B
if (match(A, m_c_Or(m_Value(X), m_Specific(B))))
- return BinaryOperator::CreateOr(Builder.CreateAnd(X, *MaskC0), B);
+ return BinaryOperator::CreateOr(Builder.CreateAnd(X, *C0), B);
// (A & MaskC) | ((X | A) & ~MaskC) -> (X & ~MaskC) | A
if (match(B, m_c_Or(m_Specific(A), m_Value(X))))
- return BinaryOperator::CreateOr(Builder.CreateAnd(X, *MaskC1), A);
+ return BinaryOperator::CreateOr(Builder.CreateAnd(X, *C1), A);
// ((X ^ B) & MaskC) | (B & ~MaskC) -> (X & MaskC) ^ B
if (match(A, m_c_Xor(m_Value(X), m_Specific(B))))
- return BinaryOperator::CreateXor(Builder.CreateAnd(X, *MaskC0), B);
+ return BinaryOperator::CreateXor(Builder.CreateAnd(X, *C0), B);
// (A & MaskC) | ((X ^ A) & ~MaskC) -> (X & ~MaskC) ^ A
if (match(B, m_c_Xor(m_Specific(A), m_Value(X))))
- return BinaryOperator::CreateXor(Builder.CreateAnd(X, *MaskC1), A);
+ return BinaryOperator::CreateXor(Builder.CreateAnd(X, *C1), A);
}
- if ((*MaskC0 & *MaskC1).isZero()) {
- // ((X | B) & C1) | (B & C2) --> (X | B) & (C1 | C2)
- // iff (C1 & C2) == 0 and (X & ~C1) == 0
+ if ((*C0 & *C1).isZero()) {
+ // ((X | B) & C0) | (B & C1) --> (X | B) & (C0 | C1)
+ // iff (C0 & C1) == 0 and (X & ~C0) == 0
if (match(A, m_c_Or(m_Value(X), m_Specific(B))) &&
- MaskedValueIsZero(X, ~*MaskC0, 0, &I))
- return BinaryOperator::CreateAnd(
- A, ConstantInt::get(I.getType(), *MaskC0 | *MaskC1));
-
- // (A & C1) | ((X | A) & C2) --> (X | A) & (C1 | C2)
- // iff (C1 & C2) == 0 and (X & ~C1) == 0
+ MaskedValueIsZero(X, ~*C0, 0, &I)) {
+ Constant *C01 = ConstantInt::get(I.getType(), *C0 | *C1);
+ return BinaryOperator::CreateAnd(A, C01);
+ }
+ // (A & C0) | ((X | A) & C1) --> (X | A) & (C0 | C1)
+ // iff (C0 & C1) == 0 and (X & ~C1) == 0
if (match(B, m_c_Or(m_Value(X), m_Specific(A))) &&
- MaskedValueIsZero(X, ~*MaskC1, 0, &I))
- return BinaryOperator::CreateAnd(
- B, ConstantInt::get(I.getType(), *MaskC0 | *MaskC1));
- }
- }
-
- // (A & C1)|(B & C2)
- ConstantInt *C1, *C2;
- if (match(C, m_ConstantInt(C1)) && match(D, m_ConstantInt(C2))) {
- if ((C1->getValue() & C2->getValue()).isZero()) {
- // ((V|C3)&C1) | ((V|C4)&C2) --> (V|C3|C4)&(C1|C2)
- // iff (C1&C2) == 0 and (C3&~C1) == 0 and (C4&~C2) == 0.
- Value *V1 = nullptr, *V2 = nullptr;
- ConstantInt *C3 = nullptr, *C4 = nullptr;
- if (match(A, m_Or(m_Value(V1), m_ConstantInt(C3))) &&
- (C3->getValue() & ~C1->getValue()).isZero() &&
- match(B, m_Or(m_Specific(V1), m_ConstantInt(C4))) &&
- (C4->getValue() & ~C2->getValue()).isZero()) {
- V2 = Builder.CreateOr(V1, ConstantExpr::getOr(C3, C4), "bitfield");
- return BinaryOperator::CreateAnd(V2,
- Builder.getInt(C1->getValue()|C2->getValue()));
+ MaskedValueIsZero(X, ~*C1, 0, &I)) {
+ Constant *C01 = ConstantInt::get(I.getType(), *C0 | *C1);
+ return BinaryOperator::CreateAnd(B, C01);
+ }
+ // ((X | C2) & C0) | ((X | C3) & C1) --> (X | C2 | C3) & (C0 | C1)
+ // iff (C0 & C1) == 0 and (C2 & ~C0) == 0 and (C3 & ~C1) == 0.
+ const APInt *C2, *C3;
+ if (match(A, m_Or(m_Value(X), m_APInt(C2))) &&
+ match(B, m_Or(m_Specific(X), m_APInt(C3))) &&
+ (*C2 & ~*C0).isZero() && (*C3 & ~*C1).isZero()) {
+ Value *Or = Builder.CreateOr(X, *C2 | *C3, "bitfield");
+ Constant *C01 = ConstantInt::get(I.getType(), *C0 | *C1);
+ return BinaryOperator::CreateAnd(Or, C01);
}
}
}
diff --git a/llvm/test/Transforms/InstCombine/and-or.ll b/llvm/test/Transforms/InstCombine/and-or.ll
index 9f5c7ab13797..2f3add7e77ee 100644
--- a/llvm/test/Transforms/InstCombine/and-or.ll
+++ b/llvm/test/Transforms/InstCombine/and-or.ll
@@ -242,7 +242,8 @@ define <2 x i8> @or_and2_or2_splat(<2 x i8> %x) {
; CHECK-NEXT: call void @use_vec(<2 x i8> [[X1]])
; CHECK-NEXT: [[X2:%.*]] = and <2 x i8> [[O2]], <i8 66, i8 66>
; CHECK-NEXT: call void @use_vec(<2 x i8> [[X2]])
-; CHECK-NEXT: [[R:%.*]] = or <2 x i8> [[X1]], [[X2]]
+; CHECK-NEXT: [[BITFIELD:%.*]] = and <2 x i8> [[X]], <i8 -8, i8 -8>
+; CHECK-NEXT: [[R:%.*]] = or <2 x i8> [[BITFIELD]], <i8 3, i8 3>
; CHECK-NEXT: ret <2 x i8> [[R]]
;
%o1 = or <2 x i8> %x, <i8 1, i8 1>
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