[llvm] 04c711c - [ConstraintElimination] Make sure the variable is available before use.

[Florian Hahn via llvm-commits]

Author: Florian Hahn
Date: 2022-09-30T18:09:01+01:00
New Revision: 04c711c78d2d2c9239b7e0c65a7a3c07d3bd89ed

URL: https://github.com/llvm/llvm-project/commit/04c711c78d2d2c9239b7e0c65a7a3c07d3bd89ed
DIFF: https://github.com/llvm/llvm-project/commit/04c711c78d2d2c9239b7e0c65a7a3c07d3bd89ed.diff

LOG: [ConstraintElimination] Make sure the variable is available before use.

This fixes a crash when trying to access an index for a value where we
don't have a known index.

Fixes #58009.

Added: 
    

Modified: 
    llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
    llvm/test/Transforms/ConstraintElimination/zext.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp b/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
index f2751e06ab59b..bc51c3b90b798 100644
--- a/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
@@ -409,7 +409,8 @@ ConstraintInfo::getConstraint(CmpInst::Predicate Pred, Value *Op0, Value *Op1,
 
   // Add extra constraints for variables that are known positive.
   for (auto &KV : KnownPositiveVariables) {
-    if (!KV.second)
+    if (!KV.second || (Value2Index.find(KV.first) == Value2Index.end() &&
+                       NewIndices.find(KV.first) == NewIndices.end()))
       continue;
     SmallVector<int64_t, 8> C(Value2Index.size() + NewIndices.size() + 1, 0);
     C[GetOrAddIndex(KV.first)] = -1;

diff  --git a/llvm/test/Transforms/ConstraintElimination/zext.ll b/llvm/test/Transforms/ConstraintElimination/zext.ll
index 3162149d64877..1101ce27ca1a8 100644
--- a/llvm/test/Transforms/ConstraintElimination/zext.ll
+++ b/llvm/test/Transforms/ConstraintElimination/zext.ll
@@ -264,3 +264,26 @@ bb2:
   %r.6 = xor i1 %r.5, %c.6
   ret i1 %r.6
 }
+
+define i1 @test_pr58009_const_zext() {
+entry:
+  %ext.t.1 = zext i1 true to i16
+  %ext.t.2 = zext i1 true to i16
+  %t.1 = icmp uge i16 %ext.t.1, %ext.t.2
+  %f.1 = icmp ugt i16 %ext.t.1, %ext.t.2
+  %res.1 = xor i1 %t.1, %f.1
+
+  %ext.f.1 = zext i1 false to i16
+  %ext.f.2 = zext i1 false to i16
+  %t.2 = icmp uge i16 %ext.f.1, %ext.f.2
+  %f.2 = icmp ugt i16 %ext.f.1, %ext.f.2
+  %res.2 = xor i1 %res.1, %t.2
+  %res.3 = xor i1 %res.2, %f.2
+
+  %t.3 = icmp ult i16 %ext.f.1, %ext.t.2
+  %f.3 = icmp ugt i16 %ext.f.1, %ext.t.2
+  %res.4 = xor i1 %res.3, %t.3
+  %res.5 = xor i1 %res.4, %f.3
+
+  ret i1 %res.5
+}