[llvm-commits] [llvm] r89483 - in /llvm/trunk: lib/Transforms/Scalar/SCCP.cpp test/Transforms/IPConstantProp/dangling-block-address.ll

[Dan Gohman]

Author: djg
Date: Fri Nov 20 14:19:14 2009
New Revision: 89483

URL: http://llvm.org/viewvc/llvm-project?rev=89483&view=rev
Log:
Fix IPSCCP's code for deleting dead blocks to tolerate outstanding
blockaddress users. This fixes PR5569.

Added:
    llvm/trunk/test/Transforms/IPConstantProp/dangling-block-address.ll
Modified:
    llvm/trunk/lib/Transforms/Scalar/SCCP.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/SCCP.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/SCCP.cpp?rev=89483&r1=89482&r2=89483&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/SCCP.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/SCCP.cpp Fri Nov 20 14:19:14 2009
@@ -1869,8 +1869,12 @@
     for (unsigned i = 0, e = BlocksToErase.size(); i != e; ++i) {
       // If there are any PHI nodes in this successor, drop entries for BB now.
       BasicBlock *DeadBB = BlocksToErase[i];
-      while (!DeadBB->use_empty()) {
-        Instruction *I = cast<Instruction>(DeadBB->use_back());
+      for (Value::use_iterator UI = DeadBB->use_begin(), UE = DeadBB->use_end();
+           UI != UE; ) {
+        // Ignore blockaddress users; BasicBlock's dtor will handle them.
+        Instruction *I = dyn_cast<Instruction>(*UI++);
+        if (!I) continue;
+
         bool Folded = ConstantFoldTerminator(I->getParent());
         if (!Folded) {
           // The constant folder may not have been able to fold the terminator

Added: llvm/trunk/test/Transforms/IPConstantProp/dangling-block-address.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/IPConstantProp/dangling-block-address.ll?rev=89483&view=auto

==============================================================================
--- llvm/trunk/test/Transforms/IPConstantProp/dangling-block-address.ll (added)
+++ llvm/trunk/test/Transforms/IPConstantProp/dangling-block-address.ll Fri Nov 20 14:19:14 2009
@@ -0,0 +1,42 @@
+; RUN: opt < %s -internalize -ipsccp -S | FileCheck %s
+; PR5569
+
+; IPSCCP should prove that the blocks are dead and delete them, and
+; properly handle the dangling blockaddress constants.
+
+; CHECK: @bar.l = internal constant [2 x i8*] [i8* inttoptr (i32 1 to i8*), i8* inttoptr (i32 1 to i8*)]
+
+ at code = global [5 x i32] [i32 0, i32 0, i32 0, i32 0, i32 1], align 4 ; <[5 x i32]*> [#uses=0]
+ at bar.l = internal constant [2 x i8*] [i8* blockaddress(@bar, %lab0), i8* blockaddress(@bar, %end)] ; <[2 x i8*]*> [#uses=1]
+
+define void @foo(i32 %x) nounwind readnone {
+entry:
+  %b = alloca i32, align 4                        ; <i32*> [#uses=1]
+  volatile store i32 -1, i32* %b
+  ret void
+}
+
+define void @bar(i32* nocapture %pc) nounwind readonly {
+entry:
+  br label %indirectgoto
+
+lab0:                                             ; preds = %indirectgoto
+  %indvar.next = add i32 %indvar, 1               ; <i32> [#uses=1]
+  br label %indirectgoto
+
+end:                                              ; preds = %indirectgoto
+  ret void
+
+indirectgoto:                                     ; preds = %lab0, %entry
+  %indvar = phi i32 [ %indvar.next, %lab0 ], [ 0, %entry ] ; <i32> [#uses=2]
+  %pc.addr.0 = getelementptr i32* %pc, i32 %indvar ; <i32*> [#uses=1]
+  %tmp1.pn = load i32* %pc.addr.0                 ; <i32> [#uses=1]
+  %indirect.goto.dest.in = getelementptr inbounds [2 x i8*]* @bar.l, i32 0, i32 %tmp1.pn ; <i8**> [#uses=1]
+  %indirect.goto.dest = load i8** %indirect.goto.dest.in ; <i8*> [#uses=1]
+  indirectbr i8* %indirect.goto.dest, [label %lab0, label %end]
+}
+
+define i32 @main() nounwind readnone {
+entry:
+  ret i32 0
+}