From 0a96144aac449114330a5264b649eb449dc19a37 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Mon, 12 Jul 2010 00:47:34 +0000
Subject: [PATCH] if jump threading is able to infer interesting values on both
the LHS and RHS of an and/or instruction, don't multiply add known
predecessor values. This fixes the crash on testcase from PR7498
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108114 91177308-0d34-0410-b5e6-96231b3b80d8
---
lib/Transforms/Scalar/JumpThreading.cpp | 15 +++++++++++++--
test/Transforms/JumpThreading/crash.ll | 24 ++++++++++++++++++++++++
2 files changed, 37 insertions(+), 2 deletions(-)
diff --git a/lib/Transforms/Scalar/JumpThreading.cpp b/lib/Transforms/Scalar/JumpThreading.cpp
index 1a64b2cbad7..f68011a08ad 100644
--- a/lib/Transforms/Scalar/JumpThreading.cpp
+++ b/lib/Transforms/Scalar/JumpThreading.cpp
@@ -346,8 +346,19 @@ ComputeValueKnownInPredecessors(Value *V, BasicBlock *BB,PredValueInfo &Result){
}
for (unsigned i = 0, e = RHSVals.size(); i != e; ++i)
if (RHSVals[i].first == InterestingVal || RHSVals[i].first == 0) {
- Result.push_back(RHSVals[i]);
- Result.back().first = InterestingVal;
+ // If we already inferred a value for this block on the LHS, don't
+ // re-add it.
+ bool HasValue = false;
+ for (unsigned r = 0, e = Result.size(); r != e; ++r)
+ if (Result[r].second == RHSVals[i].second) {
+ HasValue = true;
+ break;
+ }
+
+ if (!HasValue) {
+ Result.push_back(RHSVals[i]);
+ Result.back().first = InterestingVal;
+ }
}
return !Result.empty();
}
diff --git a/test/Transforms/JumpThreading/crash.ll b/test/Transforms/JumpThreading/crash.ll
index 378c51a44a7..480b4a04ee9 100644
--- a/test/Transforms/JumpThreading/crash.ll
+++ b/test/Transforms/JumpThreading/crash.ll
@@ -363,3 +363,27 @@ F:
ret i32 1422
}
+
+; PR7498
+define void @test14() nounwind {
+entry:
+ %cmp33 = icmp slt i8 undef, 0 ; <i1> [#uses=1]
+ %tobool = icmp eq i8 undef, 0 ; <i1> [#uses=1]
+ br i1 %tobool, label %land.end69, label %land.rhs
+
+land.rhs: ; preds = %entry
+ br label %land.end69
+
+land.end69: ; preds = %land.rhs, %entry
+ %0 = phi i1 [ undef, %land.rhs ], [ true, %entry ] ; <i1> [#uses=1]
+ %cmp71 = or i1 true, %0 ; <i1> [#uses=1]
+ %cmp73 = xor i1 %cmp33, %cmp71 ; <i1> [#uses=1]
+ br i1 %cmp73, label %if.then, label %if.end
+
+if.then: ; preds = %land.end69
+ ret void
+
+if.end: ; preds = %land.end69
+ ret void
+}
+