[llvm-commits] RFC: patch for PR1782 (BasicAliasAnalyis)

[Wojciech Matyjewicz]

Hi,

It seems that this problem is caused by a copy-paste bug in
BasicAliasAnalysis.cpp. The first part of the diff is of a cosmetic
nature. The second fixes the bug.

-Wojtek

Index: lib/Analysis/BasicAliasAnalysis.cpp
===================================================================
--- lib/Analysis/BasicAliasAnalysis.cpp (revision 44660)
+++ lib/Analysis/BasicAliasAnalysis.cpp (working copy)
@@ -730,8 +730,8 @@
           if (const ArrayType *AT = dyn_cast<ArrayType>(BasePtr1Ty)) {
             if (Op1C->getZExtValue() >= AT->getNumElements())
               return MayAlias;  // Be conservative with out-of-range accesses
-          } else if (const VectorType *PT = dyn_cast<VectorType>(BasePtr1Ty)) {
-            if (Op1C->getZExtValue() >= PT->getNumElements())
+          } else if (const VectorType *VT = dyn_cast<VectorType>(BasePtr1Ty)) {
+            if (Op1C->getZExtValue() >= VT->getNumElements())
               return MayAlias;  // Be conservative with out-of-range accesses
           }
           
@@ -756,10 +756,10 @@
       if (Op2) {
         if (const ConstantInt *Op2C = dyn_cast<ConstantInt>(Op2)) {
           // If this is an array index, make sure the array element is in 
range.
-          if (const ArrayType *AT = dyn_cast<ArrayType>(BasePtr1Ty)) {
+          if (const ArrayType *AT = dyn_cast<ArrayType>(BasePtr2Ty)) {
             if (Op2C->getZExtValue() >= AT->getNumElements())
               return MayAlias;  // Be conservative with out-of-range accesses
-          } else if (const VectorType *VT = dyn_cast<VectorType>(BasePtr1Ty)) {
+          } else if (const VectorType *VT = dyn_cast<VectorType>(BasePtr2Ty)) {
             if (Op2C->getZExtValue() >= VT->getNumElements())
               return MayAlias;  // Be conservative with out-of-range accesses
           }
Index: test/Analysis/BasicAA/2007-12-08-OutOfBoundsCrash.ll
===================================================================
--- test/Analysis/BasicAA/2007-12-08-OutOfBoundsCrash.ll        (revision 0)
+++ test/Analysis/BasicAA/2007-12-08-OutOfBoundsCrash.ll        (revision 0)
@@ -0,0 +1,31 @@
+; RUN: llvm-as < %s | opt -gvn -disable-output
+; PR1782
+
+target datalayout = 
"e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128"
+target triple = "x86_64-unknown-linux-gnu"
+       %struct.device = type { [20 x i8] }
+       %struct.pci_device_id = type { i32, i32, i32, i32, i32, i32, i64 }
+       %struct.usb_bus = type { %struct.device* }
+       %struct.usb_hcd = type { %struct.usb_bus, [0 x i64] }
[EMAIL PROTECTED] = external constant [1 x %struct.pci_device_id]               
; <[1 x %struct.pci_device_id]*> [#uses=1]
+
[EMAIL PROTECTED] = alias [1 x %struct.pci_device_id]* @pci_ids         ; <[1 x 
%struct.pci_device_id]*> [#uses=0]
+
+define i32 @ehci_pci_setup(%struct.usb_hcd* %hcd) {
+entry:
+       %tmp14 = getelementptr %struct.usb_hcd* %hcd, i32 0, i32 0, i32 0       
        ; <%struct.device**> [#uses=1]
+       %tmp15 = load %struct.device** %tmp14, align 8          ; 
<%struct.device*> [#uses=0]
+       br i1 false, label %bb25, label %return
+
+bb25:          ; preds = %entry
+       br i1 false, label %cond_true, label %return
+
+cond_true:             ; preds = %bb25
+       %tmp601 = getelementptr %struct.usb_hcd* %hcd, i32 0, i32 1, i64 
2305843009213693951            ; <i64*> [#uses=1]
+       %tmp67 = bitcast i64* %tmp601 to %struct.device**               ; 
<%struct.device**> [#uses=1]
+       %tmp68 = load %struct.device** %tmp67, align 8          ; 
<%struct.device*> [#uses=0]
+       ret i32 undef
+
+return:                ; preds = %bb25, %entry
+       ret i32 undef
+}

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