[llvm] [ConstraintElim] Use disjoint flag for decomposition (PR #74478)
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Tue Dec 5 06:34:07 PST 2023
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-llvm-transforms
Author: Nikita Popov (nikic)
<details>
<summary>Changes</summary>
Use the or disjoint flag for decomposing or into add, which will handle cases that haveNoCommonBitsSet() may not be able to reinfer (e.g. because they require context-sensitive facts, which the call here does not use.)
---
Full diff: https://github.com/llvm/llvm-project/pull/74478.diff
2 Files Affected:
- (modified) llvm/lib/Transforms/Scalar/ConstraintElimination.cpp (+1-3)
- (modified) llvm/test/Transforms/ConstraintElimination/or.ll (+105-40)
``````````diff
diff --git a/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp b/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
index 898f29f4b9ecc..a6fbddca5cba4 100644
--- a/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
@@ -544,10 +544,8 @@ static Decomposition decompose(Value *V,
}
// 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)) {
+ if (match(V, m_DisjointOr(m_Value(Op0), m_ConstantInt(CI))))
return MergeResults(Op0, CI, IsSigned);
- }
if (match(V, m_NUWShl(m_Value(Op1), m_ConstantInt(CI))) && canUseSExt(CI)) {
if (CI->getSExtValue() < 0 || CI->getSExtValue() >= 64)
diff --git a/llvm/test/Transforms/ConstraintElimination/or.ll b/llvm/test/Transforms/ConstraintElimination/or.ll
index 4f46f546bd32f..2f24519ddd1d5 100644
--- a/llvm/test/Transforms/ConstraintElimination/or.ll
+++ b/llvm/test/Transforms/ConstraintElimination/or.ll
@@ -414,20 +414,20 @@ define void @test_or_as_add_ult(i8 %init_val, i8 %high) {
; CHECK: then:
; CHECK-NEXT: [[F_0:%.*]] = icmp ult i8 [[START]], [[HIGH]]
; CHECK-NEXT: call void @use(i1 [[F_0]])
-; CHECK-NEXT: [[I_1:%.*]] = or i8 [[START]], 1
+; CHECK-NEXT: [[I_1:%.*]] = or disjoint i8 [[START]], 1
; CHECK-NEXT: [[F_1:%.*]] = icmp ult i8 [[I_1]], [[HIGH]]
; CHECK-NEXT: call void @use(i1 [[F_1]])
-; CHECK-NEXT: [[I_2:%.*]] = or i8 [[START]], 2
+; CHECK-NEXT: [[I_2:%.*]] = or disjoint i8 [[START]], 2
; CHECK-NEXT: [[F_2:%.*]] = icmp ult i8 [[I_2]], [[HIGH]]
; CHECK-NEXT: call void @use(i1 [[F_2]])
; CHECK-NEXT: ret void
; CHECK: end:
; CHECK-NEXT: call void @use(i1 true)
-; CHECK-NEXT: [[START_1:%.*]] = or i8 [[START]], 1
+; CHECK-NEXT: [[START_1:%.*]] = or disjoint i8 [[START]], 1
; CHECK-NEXT: call void @use(i1 true)
-; CHECK-NEXT: [[START_2:%.*]] = or i8 [[START]], 2
+; CHECK-NEXT: [[START_2:%.*]] = or disjoint i8 [[START]], 2
; CHECK-NEXT: call void @use(i1 true)
-; CHECK-NEXT: [[START_3:%.*]] = or i8 [[START]], 3
+; CHECK-NEXT: [[START_3:%.*]] = or disjoint i8 [[START]], 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]]
@@ -443,10 +443,10 @@ entry:
then: ; preds = %entry
%f.0 = icmp ult i8 %start, %high
call void @use(i1 %f.0)
- %i.1 = or i8 %start, 1
+ %i.1 = or disjoint i8 %start, 1
%f.1 = icmp ult i8 %i.1, %high
call void @use(i1 %f.1)
- %i.2 = or i8 %start, 2
+ %i.2 = or disjoint i8 %start, 2
%f.2 = icmp ult i8 %i.2, %high
call void @use(i1 %f.2)
ret void
@@ -454,13 +454,13 @@ then: ; preds = %entry
end: ; preds = %entry
%t.0 = icmp ult i8 %start, %high
call void @use(i1 %t.0)
- %start.1 = or i8 %start, 1
+ %start.1 = or disjoint i8 %start, 1
%t.1 = icmp ult i8 %start.1, %high
call void @use(i1 %t.1)
- %start.2 = or i8 %start, 2
+ %start.2 = or disjoint i8 %start, 2
%t.2 = icmp ult i8 %start.2, %high
call void @use(i1 %t.2)
- %start.3 = or i8 %start, 3
+ %start.3 = or disjoint i8 %start, 3
%t.3 = icmp ult i8 %start.3, %high
call void @use(i1 %t.3)
%start.4 = or i8 %start, 4
@@ -479,20 +479,20 @@ define void @test_or_as_add_ule(i8 %init_val, i8 %high) {
; CHECK: then:
; CHECK-NEXT: [[F_0:%.*]] = icmp ule i8 [[START]], [[HIGH]]
; CHECK-NEXT: call void @use(i1 [[F_0]])
-; CHECK-NEXT: [[I_1:%.*]] = or i8 [[START]], 1
+; CHECK-NEXT: [[I_1:%.*]] = or disjoint i8 [[START]], 1
; CHECK-NEXT: [[F_1:%.*]] = icmp ule i8 [[I_1]], [[HIGH]]
; CHECK-NEXT: call void @use(i1 [[F_1]])
-; CHECK-NEXT: [[I_2:%.*]] = or i8 [[START]], 2
+; CHECK-NEXT: [[I_2:%.*]] = or disjoint i8 [[START]], 2
; CHECK-NEXT: [[F_2:%.*]] = icmp ule i8 [[I_2]], [[HIGH]]
; CHECK-NEXT: call void @use(i1 [[F_2]])
; CHECK-NEXT: ret void
; CHECK: end:
; CHECK-NEXT: call void @use(i1 true)
-; CHECK-NEXT: [[START_1:%.*]] = or i8 [[START]], 1
+; CHECK-NEXT: [[START_1:%.*]] = or disjoint i8 [[START]], 1
; CHECK-NEXT: call void @use(i1 true)
-; CHECK-NEXT: [[START_2:%.*]] = or i8 [[START]], 2
+; CHECK-NEXT: [[START_2:%.*]] = or disjoint i8 [[START]], 2
; CHECK-NEXT: call void @use(i1 true)
-; CHECK-NEXT: [[START_3:%.*]] = or i8 [[START]], 3
+; CHECK-NEXT: [[START_3:%.*]] = or disjoint i8 [[START]], 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]]
@@ -511,10 +511,10 @@ entry:
then: ; preds = %entry
%f.0 = icmp ule i8 %start, %high
call void @use(i1 %f.0)
- %i.1 = or i8 %start, 1
+ %i.1 = or disjoint i8 %start, 1
%f.1 = icmp ule i8 %i.1, %high
call void @use(i1 %f.1)
- %i.2 = or i8 %start, 2
+ %i.2 = or disjoint i8 %start, 2
%f.2 = icmp ule i8 %i.2, %high
call void @use(i1 %f.2)
ret void
@@ -522,13 +522,13 @@ then: ; preds = %entry
end: ; preds = %entry
%t.0 = icmp ule i8 %start, %high
call void @use(i1 %t.0)
- %start.1 = or i8 %start, 1
+ %start.1 = or disjoint i8 %start, 1
%t.1 = icmp ule i8 %start.1, %high
call void @use(i1 %t.1)
- %start.2 = or i8 %start, 2
+ %start.2 = or disjoint i8 %start, 2
%t.2 = icmp ule i8 %start.2, %high
call void @use(i1 %t.2)
- %start.3 = or i8 %start, 3
+ %start.3 = or disjoint i8 %start, 3
%t.3 = icmp ule i8 %start.3, %high
call void @use(i1 %t.3)
%start.4 = or i8 %start, 4
@@ -551,20 +551,20 @@ define void @test_or_as_add_ugt(i8 %init_val, i8 %high) {
; CHECK: then:
; CHECK-NEXT: [[T_0:%.*]] = icmp ugt i8 [[START]], [[HIGH]]
; CHECK-NEXT: call void @use(i1 [[T_0]])
-; CHECK-NEXT: [[I_1:%.*]] = or i8 [[START]], 1
+; CHECK-NEXT: [[I_1:%.*]] = or disjoint i8 [[START]], 1
; CHECK-NEXT: [[T_1:%.*]] = icmp ugt i8 [[I_1]], [[HIGH]]
; CHECK-NEXT: call void @use(i1 [[T_1]])
-; CHECK-NEXT: [[I_2:%.*]] = or i8 [[START]], 2
+; CHECK-NEXT: [[I_2:%.*]] = or disjoint i8 [[START]], 2
; CHECK-NEXT: [[T_2:%.*]] = icmp ugt i8 [[I_2]], [[HIGH]]
; CHECK-NEXT: call void @use(i1 [[T_2]])
; CHECK-NEXT: ret void
; CHECK: end:
; CHECK-NEXT: call void @use(i1 false)
-; CHECK-NEXT: [[START_1:%.*]] = or i8 [[START]], 1
+; CHECK-NEXT: [[START_1:%.*]] = or disjoint i8 [[START]], 1
; CHECK-NEXT: call void @use(i1 false)
-; CHECK-NEXT: [[START_2:%.*]] = or i8 [[START]], 2
+; CHECK-NEXT: [[START_2:%.*]] = or disjoint i8 [[START]], 2
; CHECK-NEXT: call void @use(i1 false)
-; CHECK-NEXT: [[START_3:%.*]] = or i8 [[START]], 3
+; CHECK-NEXT: [[START_3:%.*]] = or disjoint i8 [[START]], 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]]
@@ -583,10 +583,10 @@ entry:
then: ; preds = %entry
%t.0 = icmp ugt i8 %start, %high
call void @use(i1 %t.0)
- %i.1 = or i8 %start, 1
+ %i.1 = or disjoint i8 %start, 1
%t.1 = icmp ugt i8 %i.1, %high
call void @use(i1 %t.1)
- %i.2 = or i8 %start, 2
+ %i.2 = or disjoint i8 %start, 2
%t.2 = icmp ugt i8 %i.2, %high
call void @use(i1 %t.2)
ret void
@@ -594,13 +594,13 @@ then: ; preds = %entry
end: ; preds = %entry
%f.0 = icmp ugt i8 %start, %high
call void @use(i1 %f.0)
- %start.1 = or i8 %start, 1
+ %start.1 = or disjoint i8 %start, 1
%f.1 = icmp ugt i8 %start.1, %high
call void @use(i1 %f.1)
- %start.2 = or i8 %start, 2
+ %start.2 = or disjoint i8 %start, 2
%f.2 = icmp ugt i8 %start.2, %high
call void @use(i1 %f.2)
- %start.3 = or i8 %start, 3
+ %start.3 = or disjoint i8 %start, 3
%f.3 = icmp ugt i8 %start.3, %high
call void @use(i1 %f.3)
%start.4 = or i8 %start, 4
@@ -622,20 +622,20 @@ define void @test_or_as_add_uge(i8 %init_val, i8 %high) {
; CHECK: then:
; CHECK-NEXT: [[T_0:%.*]] = icmp ugt i8 [[START]], [[HIGH]]
; CHECK-NEXT: call void @use(i1 [[T_0]])
-; CHECK-NEXT: [[I_1:%.*]] = or i8 [[START]], 1
+; CHECK-NEXT: [[I_1:%.*]] = or disjoint i8 [[START]], 1
; CHECK-NEXT: [[T_1:%.*]] = icmp uge i8 [[I_1]], [[HIGH]]
; CHECK-NEXT: call void @use(i1 [[T_1]])
-; CHECK-NEXT: [[I_2:%.*]] = or i8 [[START]], 2
+; CHECK-NEXT: [[I_2:%.*]] = or disjoint i8 [[START]], 2
; CHECK-NEXT: [[T_2:%.*]] = icmp uge i8 [[I_2]], [[HIGH]]
; CHECK-NEXT: call void @use(i1 [[T_2]])
; CHECK-NEXT: ret void
; CHECK: end:
; CHECK-NEXT: call void @use(i1 false)
-; CHECK-NEXT: [[START_1:%.*]] = or i8 [[START]], 1
+; CHECK-NEXT: [[START_1:%.*]] = or disjoint i8 [[START]], 1
; CHECK-NEXT: call void @use(i1 false)
-; CHECK-NEXT: [[START_2:%.*]] = or i8 [[START]], 2
+; CHECK-NEXT: [[START_2:%.*]] = or disjoint i8 [[START]], 2
; CHECK-NEXT: call void @use(i1 false)
-; CHECK-NEXT: [[START_3:%.*]] = or i8 [[START]], 3
+; CHECK-NEXT: [[START_3:%.*]] = or disjoint i8 [[START]], 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]]
@@ -654,10 +654,10 @@ entry:
then: ; preds = %entry
%t.0 = icmp ugt i8 %start, %high
call void @use(i1 %t.0)
- %i.1 = or i8 %start, 1
+ %i.1 = or disjoint i8 %start, 1
%t.1 = icmp uge i8 %i.1, %high
call void @use(i1 %t.1)
- %i.2 = or i8 %start, 2
+ %i.2 = or disjoint i8 %start, 2
%t.2 = icmp uge i8 %i.2, %high
call void @use(i1 %t.2)
ret void
@@ -665,13 +665,13 @@ then: ; preds = %entry
end: ; preds = %entry
%f.0 = icmp ugt i8 %start, %high
call void @use(i1 %f.0)
- %start.1 = or i8 %start, 1
+ %start.1 = or disjoint i8 %start, 1
%f.1 = icmp uge i8 %start.1, %high
call void @use(i1 %f.1)
- %start.2 = or i8 %start, 2
+ %start.2 = or disjoint i8 %start, 2
%f.2 = icmp uge i8 %start.2, %high
call void @use(i1 %f.2)
- %start.3 = or i8 %start, 3
+ %start.3 = or disjoint i8 %start, 3
%f.3 = icmp uge i8 %start.3, %high
call void @use(i1 %f.3)
%start.4 = or i8 %start, 4
@@ -748,3 +748,68 @@ end: ; preds = %entry
ret void
}
+
+; Nothing in the IR implies the disjoint flag, but we can still use it
+; to decompose into an add.
+define void @test_decompose_explicit_disjoint(i8 %start, i8 %high) {
+; CHECK-LABEL: @test_decompose_explicit_disjoint(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[START_PLUS_3:%.*]] = add nuw i8 [[START:%.*]], 3
+; CHECK-NEXT: [[C_1:%.*]] = icmp uge i8 [[START_PLUS_3]], [[HIGH:%.*]]
+; CHECK-NEXT: br i1 [[C_1]], label [[THEN:%.*]], label [[END:%.*]]
+; CHECK: then:
+; CHECK-NEXT: [[I_1:%.*]] = or disjoint i8 [[START]], 1
+; CHECK-NEXT: [[T_1:%.*]] = icmp uge i8 [[I_1]], [[HIGH]]
+; CHECK-NEXT: call void @use(i1 [[T_1]])
+; CHECK-NEXT: [[I_2:%.*]] = or disjoint i8 [[START]], 2
+; CHECK-NEXT: [[T_2:%.*]] = icmp uge i8 [[I_2]], [[HIGH]]
+; CHECK-NEXT: call void @use(i1 [[T_2]])
+; CHECK-NEXT: ret void
+; CHECK: end:
+; CHECK-NEXT: [[START_1:%.*]] = or disjoint i8 [[START]], 1
+; CHECK-NEXT: call void @use(i1 false)
+; CHECK-NEXT: [[START_2:%.*]] = or disjoint i8 [[START]], 2
+; CHECK-NEXT: call void @use(i1 false)
+; CHECK-NEXT: [[START_3:%.*]] = or disjoint i8 [[START]], 3
+; CHECK-NEXT: call void @use(i1 false)
+; CHECK-NEXT: [[START_4:%.*]] = or disjoint i8 [[START]], 4
+; CHECK-NEXT: [[C_4:%.*]] = icmp uge i8 [[START_4]], [[HIGH]]
+; CHECK-NEXT: call void @use(i1 [[C_4]])
+; CHECK-NEXT: [[START_5:%.*]] = or disjoint i8 [[START]], 5
+; CHECK-NEXT: [[C_5:%.*]] = icmp uge i8 [[START_5]], [[HIGH]]
+; CHECK-NEXT: call void @use(i1 [[C_5]])
+; CHECK-NEXT: ret void
+;
+entry:
+ %start.plus.3 = add nuw i8 %start, 3
+ %c.1 = icmp uge i8 %start.plus.3, %high
+ br i1 %c.1, label %then, label %end
+
+then: ; preds = %entry
+ %i.1 = or disjoint i8 %start, 1
+ %t.1 = icmp uge i8 %i.1, %high
+ call void @use(i1 %t.1)
+ %i.2 = or disjoint i8 %start, 2
+ %t.2 = icmp uge i8 %i.2, %high
+ call void @use(i1 %t.2)
+ ret void
+
+end: ; preds = %entry
+ %start.1 = or disjoint i8 %start, 1
+ %f.1 = icmp uge i8 %start.1, %high
+ call void @use(i1 %f.1)
+ %start.2 = or disjoint i8 %start, 2
+ %f.2 = icmp uge i8 %start.2, %high
+ call void @use(i1 %f.2)
+ %start.3 = or disjoint i8 %start, 3
+ %f.3 = icmp uge i8 %start.3, %high
+ call void @use(i1 %f.3)
+ %start.4 = or disjoint i8 %start, 4
+ %c.4 = icmp uge i8 %start.4, %high
+ call void @use(i1 %c.4)
+ %start.5 = or disjoint i8 %start, 5
+ %c.5 = icmp uge i8 %start.5, %high
+ call void @use(i1 %c.5)
+
+ ret void
+}
``````````
</details>
https://github.com/llvm/llvm-project/pull/74478
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