[llvm-commits] [llvm] r111349 - in /llvm/trunk: lib/Transforms/Scalar/JumpThreading.cpp test/Transforms/JumpThreading/crash.ll

[Chris Lattner]

Author: lattner
Date: Tue Aug 17 22:14:36 2010
New Revision: 111349

URL: http://llvm.org/viewvc/llvm-project?rev=111349&view=rev
Log:
Fix PR7755: knowing something about an inval for a pred
from the LHS should disable reconsidering that pred on the
RHS.  However, knowing something about the pred on the RHS
shouldn't disable subsequent additions on the RHS from
happening.

Modified:
    llvm/trunk/lib/Transforms/Scalar/JumpThreading.cpp
    llvm/trunk/test/Transforms/JumpThreading/crash.ll

Modified: llvm/trunk/lib/Transforms/Scalar/JumpThreading.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/JumpThreading.cpp?rev=111349&r1=111348&r2=111349&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/JumpThreading.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/JumpThreading.cpp Tue Aug 17 22:14:36 2010
@@ -341,25 +341,21 @@
       else
         InterestingVal = ConstantInt::getFalse(I->getContext());
       
+      SmallPtrSet<BasicBlock*, 4> LHSKnownBBs;
+      
       // Scan for the sentinel.  If we find an undef, force it to the
       // interesting value: x|undef -> true and x&undef -> false.
       for (unsigned i = 0, e = LHSVals.size(); i != e; ++i)
         if (LHSVals[i].first == InterestingVal || LHSVals[i].first == 0) {
           Result.push_back(LHSVals[i]);
           Result.back().first = InterestingVal;
+          LHSKnownBBs.insert(LHSVals[i].second);
         }
       for (unsigned i = 0, e = RHSVals.size(); i != e; ++i)
         if (RHSVals[i].first == InterestingVal || RHSVals[i].first == 0) {
           // 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) {
+          if (!LHSKnownBBs.count(RHSVals[i].second)) {
             Result.push_back(RHSVals[i]);
             Result.back().first = InterestingVal;
           }

Modified: llvm/trunk/test/Transforms/JumpThreading/crash.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/JumpThreading/crash.ll?rev=111349&r1=111348&r2=111349&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/JumpThreading/crash.ll (original)
+++ llvm/trunk/test/Transforms/JumpThreading/crash.ll Tue Aug 17 22:14:36 2010
@@ -436,4 +436,28 @@
   ret void
 }
 
+; PR7755
+define void @test16(i1 %c, i1 %c2, i1 %c3, i1 %c4) nounwind ssp {
+entry:
+  %cmp = icmp sgt i32 undef, 1                    ; <i1> [#uses=1]
+  br i1 %c, label %land.end, label %land.rhs
+
+land.rhs:                                         ; preds = %entry
+  br i1 %c2, label %lor.lhs.false.i, label %land.end
+
+lor.lhs.false.i:                                  ; preds = %land.rhs
+  br i1 %c3, label %land.end, label %land.end
+
+land.end:                            
+  %0 = phi i1 [ true, %entry ], [ false, %land.rhs ], [false, %lor.lhs.false.i], [false, %lor.lhs.false.i] ; <i1> [#uses=1]
+  %cmp12 = and i1 %cmp, %0 
+  %xor1 = xor i1 %cmp12, %c4
+  br i1 %xor1, label %if.then, label %if.end
+
+if.then:                      
+  ret void
+
+if.end:                       
+  ret void
+}