[llvm-commits] [llvm] r163437 - in /llvm/trunk: lib/Transforms/Utils/SimplifyCFG.cpp test/Transforms/SimplifyCFG/preserve-branchweights-partial.ll

[Andrew Trick]

Author: atrick
Date: Fri Sep  7 19:07:26 2012
New Revision: 163437

URL: http://llvm.org/viewvc/llvm-project?rev=163437&view=rev
Log:
Remove an incorrect assert during branch weight propagation.

Patch and test case by Alastair Murray!

Added:
    llvm/trunk/test/Transforms/SimplifyCFG/preserve-branchweights-partial.ll
Modified:
    llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp

Modified: llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp?rev=163437&r1=163436&r2=163437&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp Fri Sep  7 19:07:26 2012
@@ -929,7 +929,6 @@
                                 GetWeight(TI, i)->getValue().getZExtValue());
             } else if (PredHasWeights) {
               // Split the old default's weight amongst the children
-              assert(PredDefaultWeight != 0);
               Weights.push_back(PredDefaultWeight / (1 + BBCases.size()));
             }
           }

Added: llvm/trunk/test/Transforms/SimplifyCFG/preserve-branchweights-partial.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/SimplifyCFG/preserve-branchweights-partial.ll?rev=163437&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/SimplifyCFG/preserve-branchweights-partial.ll (added)
+++ llvm/trunk/test/Transforms/SimplifyCFG/preserve-branchweights-partial.ll Fri Sep  7 19:07:26 2012
@@ -0,0 +1,37 @@
+; RUN: opt -simplifycfg -S -o - < %s | FileCheck %s
+
+; This test case was written to trigger an incorrect assert statement in
+; -simplifycfg.  Thus we don't actually want to check the output, just that
+; -simplifycfg ran successfully.  Thus we only check that the function still
+; exists, and that it still calls foo().
+;
+; NOTE: There are some obviously dead blocks and missing branch weight
+;       metadata.  Both of these features were key to triggering the assert.
+;       Additionally, the not-taken weight of the branch with a weight had to
+;       be 0 to trigger the assert.
+
+declare void @foo() nounwind uwtable
+
+define void @func(i32 %A) nounwind uwtable {
+; CHECK: define void @func
+entry:
+  %cmp11 = icmp eq i32 %A, 1
+  br i1 %cmp11, label %if.then, label %if.else, !prof !0
+
+if.then:
+  call void @foo()
+; CHECK: call void @foo()
+  br label %if.else
+
+if.else:
+  %cmp17 = icmp eq i32 %A, 2
+  br i1 %cmp17, label %if.then2, label %if.end
+
+if.then2:
+  br label %if.end
+
+if.end:
+  ret void
+}
+
+!0 = metadata !{metadata !"branch_weights", i32 1, i32 0}