[llvm] 8291461 - [InstCombine] change 'not' match for bitwise select
Sanjay Patel via llvm-commits
llvm-commits at lists.llvm.org
Tue Nov 2 07:16:06 PDT 2021
Author: Sanjay Patel
Date: 2021-11-02T10:16:01-04:00
New Revision: 829146164f23701f9c5975fadb10ff2d4d100cdc
URL: https://github.com/llvm/llvm-project/commit/829146164f23701f9c5975fadb10ff2d4d100cdc
DIFF: https://github.com/llvm/llvm-project/commit/829146164f23701f9c5975fadb10ff2d4d100cdc.diff
LOG: [InstCombine] change 'not' match for bitwise select
The tests diffs are logically equivalent, and so this is
generally NFC, but this makes the code match the code
comment.
It should also be more efficient. If we choose the 'not'
operand (rather than the 'not' instruction) as the select
condition, then we don't have to invert the select
condition/operands as a subsequent transform.
Added:
Modified:
llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
llvm/test/Transforms/InstCombine/logical-select-inseltpoison.ll
llvm/test/Transforms/InstCombine/logical-select.ll
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index 3c51551ffef6f..d3b5cf3fa4b4e 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -2292,18 +2292,18 @@ static bool areInverseVectorBitmasks(Constant *C1, Constant *C2) {
/// vector composed of all-zeros or all-ones values and is the bitwise 'not' of
/// B, it can be used as the condition operand of a select instruction.
Value *InstCombinerImpl::getSelectCondition(Value *A, Value *B) {
- // Step 1: We may have peeked through bitcasts in the caller.
+ // We may have peeked through bitcasts in the caller.
// Exit immediately if we don't have (vector) integer types.
Type *Ty = A->getType();
if (!Ty->isIntOrIntVectorTy() || !B->getType()->isIntOrIntVectorTy())
return nullptr;
- // Step 2: We need 0 or all-1's bitmasks.
+ // We need 0 or all-1's bitmasks.
if (ComputeNumSignBits(A) != Ty->getScalarSizeInBits())
return nullptr;
- // Step 3: If B is the 'not' value of A, we have our answer.
- if (match(A, m_Not(m_Specific(B)))) {
+ // If B is the 'not' value of A, we have our answer.
+ if (match(B, m_Not(m_Specific(A)))) {
// If these are scalars or vectors of i1, A can be used directly.
if (Ty->isIntOrIntVectorTy(1))
return A;
diff --git a/llvm/test/Transforms/InstCombine/logical-select-inseltpoison.ll b/llvm/test/Transforms/InstCombine/logical-select-inseltpoison.ll
index ec2f47d240b86..43e97cca05bab 100644
--- a/llvm/test/Transforms/InstCombine/logical-select-inseltpoison.ll
+++ b/llvm/test/Transforms/InstCombine/logical-select-inseltpoison.ll
@@ -19,8 +19,8 @@ define i32 @foo(i32 %a, i32 %b, i32 %c, i32 %d) {
define i32 @bar(i32 %a, i32 %b, i32 %c, i32 %d) {
; CHECK-LABEL: @bar(
-; CHECK-NEXT: [[E_NOT:%.*]] = icmp slt i32 [[A:%.*]], [[B:%.*]]
-; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[E_NOT]], i32 [[C:%.*]], i32 [[D:%.*]]
+; CHECK-NEXT: [[E:%.*]] = icmp slt i32 [[A:%.*]], [[B:%.*]]
+; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[E]], i32 [[C:%.*]], i32 [[D:%.*]]
; CHECK-NEXT: ret i32 [[TMP1]]
;
%e = icmp slt i32 %a, %b
@@ -472,9 +472,9 @@ define <4 x i1> @vec_of_bools(<4 x i1> %a, <4 x i1> %b, <4 x i1> %c) {
define i4 @vec_of_casted_bools(i4 %a, i4 %b, <4 x i1> %c) {
; CHECK-LABEL: @vec_of_casted_bools(
-; CHECK-NEXT: [[TMP1:%.*]] = bitcast i4 [[A:%.*]] to <4 x i1>
-; CHECK-NEXT: [[TMP2:%.*]] = bitcast i4 [[B:%.*]] to <4 x i1>
-; CHECK-NEXT: [[TMP3:%.*]] = select <4 x i1> [[C:%.*]], <4 x i1> [[TMP2]], <4 x i1> [[TMP1]]
+; CHECK-NEXT: [[TMP1:%.*]] = bitcast i4 [[B:%.*]] to <4 x i1>
+; CHECK-NEXT: [[TMP2:%.*]] = bitcast i4 [[A:%.*]] to <4 x i1>
+; CHECK-NEXT: [[TMP3:%.*]] = select <4 x i1> [[C:%.*]], <4 x i1> [[TMP1]], <4 x i1> [[TMP2]]
; CHECK-NEXT: [[TMP4:%.*]] = bitcast <4 x i1> [[TMP3]] to i4
; CHECK-NEXT: ret i4 [[TMP4]]
;
@@ -582,8 +582,8 @@ define <4 x i32> @vec_sel_xor_multi_use(<4 x i32> %a, <4 x i32> %b, <4 x i1> %c)
define i32 @allSignBits(i32 %cond, i32 %tval, i32 %fval) {
; CHECK-LABEL: @allSignBits(
-; CHECK-NEXT: [[DOTNOT:%.*]] = icmp slt i32 [[COND:%.*]], 0
-; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[DOTNOT]], i32 [[TVAL:%.*]], i32 [[FVAL:%.*]]
+; CHECK-NEXT: [[DOTNOT:%.*]] = icmp sgt i32 [[COND:%.*]], -1
+; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[DOTNOT]], i32 [[FVAL:%.*]], i32 [[TVAL:%.*]]
; CHECK-NEXT: ret i32 [[TMP1]]
;
%bitmask = ashr i32 %cond, 31
diff --git a/llvm/test/Transforms/InstCombine/logical-select.ll b/llvm/test/Transforms/InstCombine/logical-select.ll
index 2d22f565473ae..7772d7ac6179b 100644
--- a/llvm/test/Transforms/InstCombine/logical-select.ll
+++ b/llvm/test/Transforms/InstCombine/logical-select.ll
@@ -19,8 +19,8 @@ define i32 @foo(i32 %a, i32 %b, i32 %c, i32 %d) {
define i32 @bar(i32 %a, i32 %b, i32 %c, i32 %d) {
; CHECK-LABEL: @bar(
-; CHECK-NEXT: [[E_NOT:%.*]] = icmp slt i32 [[A:%.*]], [[B:%.*]]
-; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[E_NOT]], i32 [[C:%.*]], i32 [[D:%.*]]
+; CHECK-NEXT: [[E:%.*]] = icmp slt i32 [[A:%.*]], [[B:%.*]]
+; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[E]], i32 [[C:%.*]], i32 [[D:%.*]]
; CHECK-NEXT: ret i32 [[TMP1]]
;
%e = icmp slt i32 %a, %b
@@ -472,9 +472,9 @@ define <4 x i1> @vec_of_bools(<4 x i1> %a, <4 x i1> %b, <4 x i1> %c) {
define i4 @vec_of_casted_bools(i4 %a, i4 %b, <4 x i1> %c) {
; CHECK-LABEL: @vec_of_casted_bools(
-; CHECK-NEXT: [[TMP1:%.*]] = bitcast i4 [[A:%.*]] to <4 x i1>
-; CHECK-NEXT: [[TMP2:%.*]] = bitcast i4 [[B:%.*]] to <4 x i1>
-; CHECK-NEXT: [[TMP3:%.*]] = select <4 x i1> [[C:%.*]], <4 x i1> [[TMP2]], <4 x i1> [[TMP1]]
+; CHECK-NEXT: [[TMP1:%.*]] = bitcast i4 [[B:%.*]] to <4 x i1>
+; CHECK-NEXT: [[TMP2:%.*]] = bitcast i4 [[A:%.*]] to <4 x i1>
+; CHECK-NEXT: [[TMP3:%.*]] = select <4 x i1> [[C:%.*]], <4 x i1> [[TMP1]], <4 x i1> [[TMP2]]
; CHECK-NEXT: [[TMP4:%.*]] = bitcast <4 x i1> [[TMP3]] to i4
; CHECK-NEXT: ret i4 [[TMP4]]
;
@@ -582,8 +582,8 @@ define <4 x i32> @vec_sel_xor_multi_use(<4 x i32> %a, <4 x i32> %b, <4 x i1> %c)
define i32 @allSignBits(i32 %cond, i32 %tval, i32 %fval) {
; CHECK-LABEL: @allSignBits(
-; CHECK-NEXT: [[DOTNOT:%.*]] = icmp slt i32 [[COND:%.*]], 0
-; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[DOTNOT]], i32 [[TVAL:%.*]], i32 [[FVAL:%.*]]
+; CHECK-NEXT: [[DOTNOT:%.*]] = icmp sgt i32 [[COND:%.*]], -1
+; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[DOTNOT]], i32 [[FVAL:%.*]], i32 [[TVAL:%.*]]
; CHECK-NEXT: ret i32 [[TMP1]]
;
%bitmask = ashr i32 %cond, 31
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