[llvm-commits] [llvm] r143437 - in /llvm/trunk: lib/Transforms/InstCombine/InstructionCombining.cpp test/Transforms/InstCombine/crash.ll

[Eli Friedman]

Author: efriedma
Date: Mon Oct 31 23:49:29 2011
New Revision: 143437

URL: http://llvm.org/viewvc/llvm-project?rev=143437&view=rev
Log:
Make sure we use the right insertion point when instcombine replaces a PHI with another instruction.  (Specifically, don't insert an arbitrary instruction before a PHI.)  Fixes PR11275.


Modified:
    llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp
    llvm/trunk/test/Transforms/InstCombine/crash.ll

Modified: llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp?rev=143437&r1=143436&r2=143437&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp Mon Oct 31 23:49:29 2011
@@ -2028,9 +2028,10 @@
         BasicBlock *InstParent = I->getParent();
         BasicBlock::iterator InsertPos = I;
 
-        if (!isa<PHINode>(Result))        // If combining a PHI, don't insert
-          while (isa<PHINode>(InsertPos)) // middle of a block of PHIs.
-            ++InsertPos;
+        // If we replace a PHI with something that isn't a PHI, fix up the
+        // insertion point.
+        if (!isa<PHINode>(Result) && isa<PHINode>(InsertPos))
+          InsertPos = InstParent->getFirstInsertionPt();
 
         InstParent->getInstList().insert(InsertPos, Result);
 

Modified: llvm/trunk/test/Transforms/InstCombine/crash.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/crash.ll?rev=143437&r1=143436&r2=143437&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/crash.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/crash.ll Mon Oct 31 23:49:29 2011
@@ -374,3 +374,28 @@
 return:                                           ; No predecessors!
   ret void
 }
+
+; PR11275
+declare void @test18b() noreturn
+declare void @test18foo(double**)
+declare void @test18a() noreturn
+define fastcc void @test18x(i8* %t0, i1 %b) uwtable align 2 {
+entry:
+  br i1 %b, label %e1, label %e2
+e1:
+  %t2 = bitcast i8* %t0 to double**
+  invoke void @test18b() noreturn
+          to label %u unwind label %lpad
+e2:
+  %t4 = bitcast i8* %t0 to double**
+  invoke void @test18a() noreturn
+          to label %u unwind label %lpad
+lpad:
+  %t5 = phi double** [ %t2, %e1 ], [ %t4, %e2 ]
+  %lpad.nonloopexit262 = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
+          cleanup
+  call void @test18foo(double** %t5)
+  unreachable
+u:
+  unreachable
+}