[llvm-commits] [llvm] r43949 - in /llvm/trunk: lib/Transforms/IPO/GlobalOpt.cpp test/Transforms/GlobalOpt/2007-11-09-GEP-GEP-Crash.ll

[Chris Lattner]

Author: lattner
Date: Fri Nov  9 11:33:02 2007
New Revision: 43949

URL: http://llvm.org/viewvc/llvm-project?rev=43949&view=rev
Log:
Tighten up a check for folding away loads from (newly constant) globals.  This
fixes a crash on Transforms/GlobalOpt/2007-11-09-GEP-GEP-Crash.ll and 
rdar://5585488.

Added:
    llvm/trunk/test/Transforms/GlobalOpt/2007-11-09-GEP-GEP-Crash.ll
Modified:
    llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp

Modified: llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp?rev=43949&r1=43948&r2=43949&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp (original)
+++ llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp Fri Nov  9 11:33:02 2007
@@ -342,12 +342,17 @@
         Changed = true;
       }
     } else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(U)) {
-      Constant *SubInit = 0;
-      ConstantExpr *CE = 
-        dyn_cast_or_null<ConstantExpr>(ConstantFoldInstruction(GEP));
-      if (Init && CE && CE->getOpcode() == Instruction::GetElementPtr)
-        SubInit = ConstantFoldLoadThroughGEPConstantExpr(Init, CE);
-      Changed |= CleanupConstantGlobalUsers(GEP, SubInit);
+      // Do not transform "gepinst (gep constexpr (GV))" here, because forming
+      // "gepconstexpr (gep constexpr (GV))" will cause the two gep's to fold
+      // and will invalidate our notion of what Init is.
+      if (!isa<ConstantExpr>(GEP->getOperand(0))) {
+        ConstantExpr *CE = 
+          dyn_cast_or_null<ConstantExpr>(ConstantFoldInstruction(GEP));
+        if (Init && CE && CE->getOpcode() == Instruction::GetElementPtr)
+          if (Constant *SubInit = 
+              ConstantFoldLoadThroughGEPConstantExpr(Init, CE))
+            Changed |= CleanupConstantGlobalUsers(GEP, SubInit);
+      }
 
       if (GEP->use_empty()) {
         GEP->eraseFromParent();

Added: llvm/trunk/test/Transforms/GlobalOpt/2007-11-09-GEP-GEP-Crash.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/GlobalOpt/2007-11-09-GEP-GEP-Crash.ll?rev=43949&view=auto

==============================================================================
--- llvm/trunk/test/Transforms/GlobalOpt/2007-11-09-GEP-GEP-Crash.ll (added)
+++ llvm/trunk/test/Transforms/GlobalOpt/2007-11-09-GEP-GEP-Crash.ll Fri Nov  9 11:33:02 2007
@@ -0,0 +1,19 @@
+; RUN: llvm-as < %s | opt -globalopt -disable-output
+target datalayout = "E-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f128:64:128"
+target triple = "powerpc-apple-darwin8"
+        %struct.empty0 = type {  }
+        %struct.es = type { %struct.empty0 }
+        %struct.es1 = type { %struct.empty0 }
+ at aaui1 = internal global [6 x [2 x i32]] [ [2 x i32] [ i32 1, i32 1 ], [2 x i32] [ i32 1, i32 1 ], [2 x i32] [ i32 1, i32 1 ], [2 x i32] [ i32 1, i32 1 ], [2 x i32] [ i32 1, i32 1 ], [2 x i32] [ i32 1, i32 1 ] ]              ; <[6 x [2 x i32]]*> [#uses=1]
+ at aaui0 = internal global [0 x [2 x i32]] zeroinitializer                ; <[0 x [2 x i32]]*> [#uses=1]
+
+define i8 @func() {
+entry:
+        %tmp10 = getelementptr [2 x i32]* getelementptr ([6 x [2 x i32]]* @aaui1, i32 0, i32 0), i32 5, i32 1           ; <i32*> [#uses=1]
+        %tmp11 = load i32* %tmp10, align 4              ; <i32> [#uses=1]
+        %tmp12 = call i32 (...)* @func3( i32* null, i32 0, i32 %tmp11 )         ; <i32> [#uses=0]
+        ret i8 undef
+}
+
+declare i32 @func3(...)
+