[llvm-commits] [llvm] r71536 - in /llvm/trunk: lib/CodeGen/CodePlacementOpt.cpp test/CodeGen/ARM/2009-05-11-CodePlacementCrash.ll

[Bob Wilson]

Author: bwilson
Date: Mon May 11 22:48:10 2009
New Revision: 71536

URL: http://llvm.org/viewvc/llvm-project?rev=71536&view=rev
Log:
Fix pr4195: When iterating through predecessor blocks, break out of the loop
after finding the (unique) layout predecessor.  Sometimes a block may be listed
more than once, and processing it more than once in this loop can lead to
inconsistent values for FtTBB/FtFBB, since the AnalyzeBranch method does not
clear these values.  There's no point in continuing the loop regardless.
The testcase for this is reduced from the 2003-05-02-DependentPHI SingleSource
test.

Added:
    llvm/trunk/test/CodeGen/ARM/2009-05-11-CodePlacementCrash.ll
Modified:
    llvm/trunk/lib/CodeGen/CodePlacementOpt.cpp

Modified: llvm/trunk/lib/CodeGen/CodePlacementOpt.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/CodePlacementOpt.cpp?rev=71536&r1=71535&r2=71536&view=diff

==============================================================================
--- llvm/trunk/lib/CodeGen/CodePlacementOpt.cpp (original)
+++ llvm/trunk/lib/CodeGen/CodePlacementOpt.cpp Mon May 11 22:48:10 2009
@@ -155,10 +155,10 @@
         // A fallthrough.
         FtMBB = PredMBB;
         MachineLoop *PL = MLI->getLoopFor(PredMBB);
-        if (PL && (PL == L || PL->getLoopDepth() >= L->getLoopDepth())) {
+        if (PL && (PL == L || PL->getLoopDepth() >= L->getLoopDepth()))
           OkToMove = false;
-          break;
-        }
+
+        break;
       }
     }
 

Added: llvm/trunk/test/CodeGen/ARM/2009-05-11-CodePlacementCrash.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/2009-05-11-CodePlacementCrash.ll?rev=71536&view=auto

==============================================================================
--- llvm/trunk/test/CodeGen/ARM/2009-05-11-CodePlacementCrash.ll (added)
+++ llvm/trunk/test/CodeGen/ARM/2009-05-11-CodePlacementCrash.ll Mon May 11 22:48:10 2009
@@ -0,0 +1,30 @@
+; RUN: llvm-as < %s | llc -march=arm
+	%struct.List = type { %struct.List*, i32 }
+ at Node5 = external constant %struct.List		; <%struct.List*> [#uses=1]
+@"\01LC" = external constant [7 x i8]		; <[7 x i8]*> [#uses=1]
+
+define i32 @main() nounwind {
+entry:
+	br label %bb
+
+bb:		; preds = %bb3, %entry
+	%CurL.02 = phi %struct.List* [ @Node5, %entry ], [ %2, %bb3 ]		; <%struct.List*> [#uses=1]
+	%PrevL.01 = phi %struct.List* [ null, %entry ], [ %CurL.02, %bb3 ]		; <%struct.List*> [#uses=1]
+	%0 = icmp eq %struct.List* %PrevL.01, null		; <i1> [#uses=1]
+	br i1 %0, label %bb3, label %bb1
+
+bb1:		; preds = %bb
+	br label %bb3
+
+bb3:		; preds = %bb1, %bb
+	%iftmp.0.0 = phi i32 [ 0, %bb1 ], [ -1, %bb ]		; <i32> [#uses=1]
+	%1 = tail call i32 (i8*, ...)* @printf(i8* getelementptr ([7 x i8]* @"\01LC", i32 0, i32 0), i32 0, i32 %iftmp.0.0) nounwind		; <i32> [#uses=0]
+	%2 = load %struct.List** null, align 4		; <%struct.List*> [#uses=2]
+	%phitmp = icmp eq %struct.List* %2, null		; <i1> [#uses=1]
+	br i1 %phitmp, label %bb5, label %bb
+
+bb5:		; preds = %bb3
+	ret i32 0
+}
+
+declare i32 @printf(i8* nocapture, ...) nounwind