[llvm] [ValueLattice] Reset the count of range extensions when merging an undef with a constant range. (PR #77307)
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Mon Jan 8 06:01:18 PST 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-llvm-analysis
Author: Yingwei Zheng (dtcxzyw)
<details>
<summary>Changes</summary>
This patch resets `NumRangeExtensions` to zero when merging an undef with a constant range.
This change also matches the behavior of `markConstantRange`:
https://github.com/llvm/llvm-project/blob/4a456489e051ff037655597a0b54654aa1f5a2a5/llvm/include/llvm/Analysis/ValueLattice.h#L375-L380
Fixes a regression caused by https://github.com/llvm/llvm-project/pull/76295.
See also https://github.com/dtcxzyw/llvm-opt-benchmark/pull/36#issuecomment-1880865241.
---
Full diff: https://github.com/llvm/llvm-project/pull/77307.diff
2 Files Affected:
- (modified) llvm/include/llvm/Analysis/ValueLattice.h (+1)
- (added) llvm/test/Transforms/SCCP/widen-steps-limit.ll (+91)
``````````diff
diff --git a/llvm/include/llvm/Analysis/ValueLattice.h b/llvm/include/llvm/Analysis/ValueLattice.h
index 2898cdd3d7b0ca..196d7d11e13da4 100644
--- a/llvm/include/llvm/Analysis/ValueLattice.h
+++ b/llvm/include/llvm/Analysis/ValueLattice.h
@@ -406,6 +406,7 @@ class ValueLatticeElement {
if (isUnknown()) {
assert(!RHS.isUnknown() && "Unknow RHS should be handled earlier");
*this = RHS;
+ NumRangeExtensions = 0;
return true;
}
diff --git a/llvm/test/Transforms/SCCP/widen-steps-limit.ll b/llvm/test/Transforms/SCCP/widen-steps-limit.ll
new file mode 100644
index 00000000000000..98224c4d495705
--- /dev/null
+++ b/llvm/test/Transforms/SCCP/widen-steps-limit.ll
@@ -0,0 +1,91 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
+; RUN: opt -S -passes=sccp < %s | FileCheck %s
+
+define void @test() {
+; CHECK-LABEL: define void @test() {
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[TMP0:%.*]] = tail call i8 @geti8()
+; CHECK-NEXT: [[CONV_I:%.*]] = zext i8 [[TMP0]] to i32
+; CHECK-NEXT: [[CMP19_I_NOT:%.*]] = tail call i1 @geti1()
+; CHECK-NEXT: br i1 [[CMP19_I_NOT]], label [[WHILE_END_I_THREAD:%.*]], label [[EXIT2:%.*]]
+; CHECK: while.end.i.thread:
+; CHECK-NEXT: [[TMP1:%.*]] = tail call i1 @geti1()
+; CHECK-NEXT: [[TMP2:%.*]] = zext i1 [[TMP1]] to i32
+; CHECK-NEXT: br label [[EXIT2]]
+; CHECK: exit2:
+; CHECK-NEXT: [[CMP_I12_I4:%.*]] = phi i32 [ [[TMP2]], [[WHILE_END_I_THREAD]] ], [ 0, [[ENTRY:%.*]] ]
+; CHECK-NEXT: [[CMP:%.*]] = tail call i1 @geti1()
+; CHECK-NEXT: br i1 [[CMP]], label [[IF_THEN6:%.*]], label [[IF_END_I_I:%.*]]
+; CHECK: if.then6:
+; CHECK-NEXT: [[CMP_I32:%.*]] = icmp ugt i32 [[CMP_I12_I4]], [[CONV_I]]
+; CHECK-NEXT: br i1 [[CMP_I32]], label [[EXIT:%.*]], label [[COND_FALSE_I:%.*]]
+; CHECK: cond.false.i:
+; CHECK-NEXT: [[CMP_NOT6_I_I:%.*]] = tail call i1 @geti1()
+; CHECK-NEXT: br i1 [[CMP_NOT6_I_I]], label [[EXIT]], label [[FOR_BODY_PREHEADER_I_I:%.*]]
+; CHECK: for.body.preheader.i.i:
+; CHECK-NEXT: [[CMP_NOT_I_I:%.*]] = tail call i1 @geti1()
+; CHECK-NEXT: br label [[EXIT]]
+; CHECK: exit:
+; CHECK-NEXT: [[RETVAL_SROA_3_0_I:%.*]] = phi i32 [ 0, [[IF_THEN6]] ], [ 1, [[COND_FALSE_I]] ], [ 1, [[FOR_BODY_PREHEADER_I_I]] ]
+; CHECK-NEXT: br i1 [[CMP19_I_NOT]], label [[IF_END_I_I]], label [[DO_BODY_I_I:%.*]]
+; CHECK: do.body.i.i:
+; CHECK-NEXT: br label [[IF_END_I_I]]
+; CHECK: if.end.i.i:
+; CHECK-NEXT: ret void
+;
+entry:
+ %0 = tail call i8 @geti8()
+ %conv.i = zext i8 %0 to i32
+ %cmp19.i.not = tail call i1 @geti1()
+ br i1 %cmp19.i.not, label %while.end.i.thread, label %exit2
+
+while.end.i.thread: ; preds = %entry
+ %1 = tail call i1 @geti1()
+ %2 = zext i1 %1 to i32
+ br label %exit2
+
+exit2: ; preds = %while.end.i.thread, %entry
+ %cmp.i12.i4 = phi i32 [ %2, %while.end.i.thread ], [ 0, %entry ]
+ %cmp = tail call i1 @geti1()
+ br i1 %cmp, label %if.then6, label %if.end.i.i
+
+if.then6: ; preds = %exit2
+ %cmp.i32 = icmp ugt i32 %cmp.i12.i4, %conv.i
+ br i1 %cmp.i32, label %exit, label %cond.false.i
+
+cond.false.i: ; preds = %if.then6
+ %cmp.not6.i.i = tail call i1 @geti1()
+ br i1 %cmp.not6.i.i, label %exit, label %for.body.preheader.i.i
+
+for.body.preheader.i.i: ; preds = %cond.false.i
+ %cmp.not.i.i = tail call i1 @geti1()
+ br label %exit
+
+exit: ; preds = %for.body.preheader.i.i, %cond.false.i, %if.then6
+ %retval.sroa.3.0.i = phi i32 [ 0, %if.then6 ], [ 1, %cond.false.i ], [ 1, %for.body.preheader.i.i ]
+ br i1 %cmp19.i.not, label %if.end.i.i, label %do.body.i.i
+
+do.body.i.i: ; preds = %exit, %do.cond.i.i
+ %result.sroa.7.0.i.i = phi i32 [ %result.sroa.7.1.i.i, %do.cond.i.i ], [ %retval.sroa.3.0.i, %exit ]
+ switch i32 %result.sroa.7.0.i.i, label %do.cond.i.i [
+ i32 2, label %sw.bb.i.i
+ i32 1, label %if.end.i.i
+ i32 0, label %if.end.i.i
+ ]
+
+sw.bb.i.i: ; preds = %do.body.i.i
+ %3 = tail call i32 @geti32()
+ br label %do.cond.i.i
+
+do.cond.i.i: ; preds = %sw.bb.i.i, %do.body.i.i
+ %result.sroa.7.1.i.i = phi i32 [ %result.sroa.7.0.i.i, %do.body.i.i ], [ %3, %sw.bb.i.i ]
+ %cmp22.i.i = tail call i1 @geti1()
+ br i1 %cmp22.i.i, label %do.body.i.i, label %if.end.i.i
+
+if.end.i.i: ; preds = %do.cond.i.i, %do.body.i.i, %do.body.i.i, %exit, %exit2
+ ret void
+}
+
+declare i8 @geti8()
+declare i32 @geti32()
+declare i1 @geti1()
``````````
</details>
https://github.com/llvm/llvm-project/pull/77307
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