[llvm] 2b62774 - [ConstraintElimination] Decompose or instruction if the constant operand < 2^known_zero_bits of the first operand.
Zain Jaffal via llvm-commits
llvm-commits at lists.llvm.org
Tue Mar 7 06:11:47 PST 2023
Author: Zain Jaffal
Date: 2023-03-07T14:11:35Z
New Revision: 2b62774b653affb7e5ef35e25745e80612b990a9
URL: https://github.com/llvm/llvm-project/commit/2b62774b653affb7e5ef35e25745e80612b990a9
DIFF: https://github.com/llvm/llvm-project/commit/2b62774b653affb7e5ef35e25745e80612b990a9.diff
LOG: [ConstraintElimination] Decompose or instruction if the constant operand < 2^known_zero_bits of the first operand.
The or operation can be represented as an add instruction.
Reviewed By: fhahn
Differential Revision: https://reviews.llvm.org/D142546
Added:
Modified:
llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
llvm/test/Transforms/ConstraintElimination/or.ll
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp b/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
index 2aa76c6c4130a..f660e73781d59 100644
--- a/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
@@ -32,6 +32,7 @@
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/DebugCounter.h"
+#include "llvm/Support/KnownBits.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Transforms/Utils/ValueMapper.h"
@@ -369,6 +370,12 @@ static Decomposition decompose(Value *V,
return MergeResults(Op0, CI, true);
}
+ // Decompose or as an add if there are no common bits between the operands.
+ if (match(V, m_Or(m_Value(Op0), m_ConstantInt(CI))) &&
+ haveNoCommonBitsSet(Op0, CI, DL)) {
+ return MergeResults(Op0, CI, IsSigned);
+ }
+
if (match(V, m_NUWShl(m_Value(Op1), m_ConstantInt(CI))) && canUseSExt(CI)) {
int64_t Mult = int64_t(std::pow(int64_t(2), CI->getSExtValue()));
auto Result = decompose(Op1, Preconditions, IsSigned, DL);
diff --git a/llvm/test/Transforms/ConstraintElimination/or.ll b/llvm/test/Transforms/ConstraintElimination/or.ll
index 4fa8edd83c291..511aef06ce2f2 100644
--- a/llvm/test/Transforms/ConstraintElimination/or.ll
+++ b/llvm/test/Transforms/ConstraintElimination/or.ll
@@ -454,13 +454,13 @@ define void @test_or_as_add_ult(i8 %init_val, i8 %high) {
; CHECK-NEXT: call void @use(i1 true)
; CHECK-NEXT: [[START_1:%.*]] = or i8 [[START]], 1
; CHECK-NEXT: [[T_1:%.*]] = icmp ult i8 [[START_1]], [[HIGH]]
-; CHECK-NEXT: call void @use(i1 [[T_1]])
+; CHECK-NEXT: call void @use(i1 true)
; CHECK-NEXT: [[START_2:%.*]] = or i8 [[START]], 2
; CHECK-NEXT: [[T_2:%.*]] = icmp ult i8 [[START_2]], [[HIGH]]
-; CHECK-NEXT: call void @use(i1 [[T_2]])
+; CHECK-NEXT: call void @use(i1 true)
; CHECK-NEXT: [[START_3:%.*]] = or i8 [[START]], 3
; CHECK-NEXT: [[T_3:%.*]] = icmp ult i8 [[START_3]], [[HIGH]]
-; CHECK-NEXT: call void @use(i1 [[T_3]])
+; CHECK-NEXT: call void @use(i1 true)
; CHECK-NEXT: [[START_4:%.*]] = or i8 [[START]], 4
; CHECK-NEXT: [[C_4:%.*]] = icmp ult i8 [[START_4]], [[HIGH]]
; CHECK-NEXT: call void @use(i1 [[C_4]])
@@ -523,13 +523,13 @@ define void @test_or_as_add_ule(i8 %init_val, i8 %high) {
; CHECK-NEXT: call void @use(i1 true)
; CHECK-NEXT: [[START_1:%.*]] = or i8 [[START]], 1
; CHECK-NEXT: [[T_1:%.*]] = icmp ule i8 [[START_1]], [[HIGH]]
-; CHECK-NEXT: call void @use(i1 [[T_1]])
+; CHECK-NEXT: call void @use(i1 true)
; CHECK-NEXT: [[START_2:%.*]] = or i8 [[START]], 2
; CHECK-NEXT: [[T_2:%.*]] = icmp ule i8 [[START_2]], [[HIGH]]
-; CHECK-NEXT: call void @use(i1 [[T_2]])
+; CHECK-NEXT: call void @use(i1 true)
; CHECK-NEXT: [[START_3:%.*]] = or i8 [[START]], 3
; CHECK-NEXT: [[T_3:%.*]] = icmp ule i8 [[START_3]], [[HIGH]]
-; CHECK-NEXT: call void @use(i1 [[T_3]])
+; CHECK-NEXT: call void @use(i1 true)
; CHECK-NEXT: [[START_4:%.*]] = or i8 [[START]], 4
; CHECK-NEXT: [[T_4:%.*]] = icmp ule i8 [[START_4]], [[HIGH]]
; CHECK-NEXT: call void @use(i1 [[T_4]])
@@ -599,13 +599,13 @@ define void @test_or_as_add_ugt(i8 %init_val, i8 %high) {
; CHECK-NEXT: call void @use(i1 false)
; CHECK-NEXT: [[START_1:%.*]] = or i8 [[START]], 1
; CHECK-NEXT: [[F_1:%.*]] = icmp ugt i8 [[START_1]], [[HIGH]]
-; CHECK-NEXT: call void @use(i1 [[F_1]])
+; CHECK-NEXT: call void @use(i1 false)
; CHECK-NEXT: [[START_2:%.*]] = or i8 [[START]], 2
; CHECK-NEXT: [[F_2:%.*]] = icmp ugt i8 [[START_2]], [[HIGH]]
-; CHECK-NEXT: call void @use(i1 [[F_2]])
+; CHECK-NEXT: call void @use(i1 false)
; CHECK-NEXT: [[START_3:%.*]] = or i8 [[START]], 3
; CHECK-NEXT: [[F_3:%.*]] = icmp ugt i8 [[START_3]], [[HIGH]]
-; CHECK-NEXT: call void @use(i1 [[F_3]])
+; CHECK-NEXT: call void @use(i1 false)
; CHECK-NEXT: [[START_4:%.*]] = or i8 [[START]], 4
; CHECK-NEXT: [[F_4:%.*]] = icmp ugt i8 [[START_4]], [[HIGH]]
; CHECK-NEXT: call void @use(i1 [[F_4]])
@@ -674,13 +674,13 @@ define void @test_or_as_add_uge(i8 %init_val, i8 %high) {
; CHECK-NEXT: call void @use(i1 false)
; CHECK-NEXT: [[START_1:%.*]] = or i8 [[START]], 1
; CHECK-NEXT: [[F_1:%.*]] = icmp uge i8 [[START_1]], [[HIGH]]
-; CHECK-NEXT: call void @use(i1 [[F_1]])
+; CHECK-NEXT: call void @use(i1 false)
; CHECK-NEXT: [[START_2:%.*]] = or i8 [[START]], 2
; CHECK-NEXT: [[F_2:%.*]] = icmp uge i8 [[START_2]], [[HIGH]]
-; CHECK-NEXT: call void @use(i1 [[F_2]])
+; CHECK-NEXT: call void @use(i1 false)
; CHECK-NEXT: [[START_3:%.*]] = or i8 [[START]], 3
; CHECK-NEXT: [[F_3:%.*]] = icmp uge i8 [[START_3]], [[HIGH]]
-; CHECK-NEXT: call void @use(i1 [[F_3]])
+; CHECK-NEXT: call void @use(i1 false)
; CHECK-NEXT: [[START_4:%.*]] = or i8 [[START]], 4
; CHECK-NEXT: [[C_4:%.*]] = icmp uge i8 [[START_4]], [[HIGH]]
; CHECK-NEXT: call void @use(i1 [[C_4]])
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