From 2812a1413f19b9ebd954b57ecbd021656508eade Mon Sep 17 00:00:00 2001
From: Florian Hahn <flo@fhahn.com>
Date: Fri, 30 Sep 2022 19:37:58 +0100
Subject: [PATCH] [ConstraintElimination] Add test showing bug in analysis
 invalidation.

---
 .../ConstraintElimination/analysis-invalidation.ll | 66 ++++++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100644 llvm/test/Transforms/ConstraintElimination/analysis-invalidation.ll

diff --git a/llvm/test/Transforms/ConstraintElimination/analysis-invalidation.ll b/llvm/test/Transforms/ConstraintElimination/analysis-invalidation.ll
new file mode 100644
index 0000000..ecd0677
--- /dev/null
+++ b/llvm/test/Transforms/ConstraintElimination/analysis-invalidation.ll
@@ -0,0 +1,66 @@
+; RUN: opt -passes='require<demanded-bits>,constraint-elimination,require<demanded-bits>' -disable-verify -verify-cfg-preserved -debug-pass-manager -disable-output %s 2>&1 | FileCheck %s
+
+; Check that constraint-elimination properly invalidates anlyses.
+
+; FIXME: ssub simplification currently doesn't properly set the change status
+;        after modifying the IR, which causes DemandedBits to be preserved.
+
+; CHECK:      Running analysis: InnerAnalysisManagerProxy<llvm::FunctionAnalysisManager, llvm::Module> on [module]
+; CHECK-NEXT: Running analysis: PreservedCFGCheckerAnalysis on ssub_no_overflow_due_to_or_conds
+; CHECK-NEXT: Running pass: RequireAnalysisPass<llvm::DemandedBitsAnalysis, llvm::Function> on ssub_no_overflow_due_to_or_conds
+; CHECK-NEXT: Running analysis: DemandedBitsAnalysis on ssub_no_overflow_due_to_or_conds
+; CHECK-NEXT: Running analysis: AssumptionAnalysis on ssub_no_overflow_due_to_or_conds
+; CHECK-NEXT: Running analysis: TargetIRAnalysis on ssub_no_overflow_due_to_or_conds
+; CHECK-NEXT: Running analysis: DominatorTreeAnalysis on ssub_no_overflow_due_to_or_conds
+; CHECK-NEXT: Running pass: ConstraintEliminationPass on ssub_no_overflow_due_to_or_conds (10 instructions)
+; CHECK-NEXT: Running pass: RequireAnalysisPass<llvm::DemandedBitsAnalysis, llvm::Function> on ssub_no_overflow_due_to_or_conds
+
+; CHECK-NEXT: Running analysis: PreservedCFGCheckerAnalysis on uge_zext
+; CHECK-NEXT: Running pass: RequireAnalysisPass<llvm::DemandedBitsAnalysis, llvm::Function> on uge_zext (6 instructions)
+; CHECK-NEXT: Running analysis: DemandedBitsAnalysis on uge_zext
+; CHECK-NEXT: Running analysis: AssumptionAnalysis on uge_zext
+; CHECK-NEXT: Running analysis: TargetIRAnalysis on uge_zext
+; CHECK-NEXT: Running analysis: DominatorTreeAnalysis on uge_zext
+; CHECK-NEXT: Running pass: ConstraintEliminationPass on uge_zext (6 instructions)
+; CHECK-NEXT: Invalidating analysis: DemandedBitsAnalysis on uge_zext
+; CHECK-NEXT: Running pass: RequireAnalysisPass<llvm::DemandedBitsAnalysis, llvm::Function> on uge_zext (6 instructions)
+; CHECK-NEXT: Running analysis: DemandedBitsAnalysis on uge_zext
+
+declare { i8, i1 } @llvm.ssub.with.overflow.i8(i8, i8)
+
+define i8 @ssub_no_overflow_due_to_or_conds(i8 %a, i8 %b) {
+entry:
+  %c.1 = icmp sle i8 %b, %a
+  %c.2 = icmp slt i8 %a, 0
+  %or.cond = or i1 %c.2, %c.1
+  br i1 %or.cond, label %exit.fail, label %math
+
+math:
+  %op = tail call { i8, i1 } @llvm.ssub.with.overflow.i8(i8 %b, i8 %a)
+  %status = extractvalue { i8, i1 } %op, 1
+  br i1 %status, label %exit.fail, label %exit.ok
+
+exit.ok:
+  %res = extractvalue { i8, i1 } %op, 0
+  ret i8 %res
+
+exit.fail:
+  ret i8 0
+}
+
+declare void @use_res({ i8, i1 })
+
+
+define i1 @uge_zext(i8 %x, i16 %y) {
+entry:
+  %x.ext = zext i8 %x to i16
+  %c.1 = icmp uge i16 %x.ext, %y
+  br i1 %c.1, label %bb1, label %bb2
+
+bb1:
+  %t.1 = icmp uge i16 %x.ext, %y
+  ret i1 %t.1
+
+bb2:
+  ret i1 false
+}
-- 
2.7.4