[llvm-commits] [llvm] r96950 - in /llvm/trunk: lib/Analysis/ConstantFolding.cpp test/Transforms/InstCombine/constant-fold-ptr-casts.ll

[Dan Gohman]

Author: djg
Date: Tue Feb 23 10:35:41 2010
New Revision: 96950

URL: http://llvm.org/viewvc/llvm-project?rev=96950&view=rev
Log:
Remove the code which constant-folded ptrtoint(inttoptr(x)+c) to
getelementptr. Despite only doing so in the case where x is a known
array object and c can be converted to an index within range, this
could still be invalid if c is actually the address of an object
allocated outside of LLVM. Also, SCEVExpander, the original motivation
for this code, has since been improved to avoid inttoptr+ptroint in
more cases.

Removed:
    llvm/trunk/test/Transforms/InstCombine/constant-fold-ptr-casts.ll
Modified:
    llvm/trunk/lib/Analysis/ConstantFolding.cpp

Modified: llvm/trunk/lib/Analysis/ConstantFolding.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ConstantFolding.cpp?rev=96950&r1=96949&r2=96950&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ConstantFolding.cpp (original)
+++ llvm/trunk/lib/Analysis/ConstantFolding.cpp Tue Feb 23 10:35:41 2010
@@ -783,44 +783,12 @@
     // If the input is a ptrtoint, turn the pair into a ptr to ptr bitcast if
     // the int size is >= the ptr size.  This requires knowing the width of a
     // pointer, so it can't be done in ConstantExpr::getCast.
-    if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Ops[0])) {
+    if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Ops[0]))
       if (TD &&
-          TD->getPointerSizeInBits() <=
-          CE->getType()->getScalarSizeInBits()) {
-        if (CE->getOpcode() == Instruction::PtrToInt)
-          return FoldBitCast(CE->getOperand(0), DestTy, *TD);
-        
-        // If there's a constant offset added to the integer value before
-        // it is casted back to a pointer, see if the expression can be
-        // converted into a GEP.
-        if (CE->getOpcode() == Instruction::Add)
-          if (ConstantInt *L = dyn_cast<ConstantInt>(CE->getOperand(1)))
-            if (ConstantExpr *R = dyn_cast<ConstantExpr>(CE->getOperand(0)))
-              if (R->getOpcode() == Instruction::PtrToInt)
-                if (GlobalVariable *GV =
-                      dyn_cast<GlobalVariable>(R->getOperand(0))) {
-                  const PointerType *GVTy = cast<PointerType>(GV->getType());
-                  if (const ArrayType *AT =
-                        dyn_cast<ArrayType>(GVTy->getElementType())) {
-                    const Type *ElTy = AT->getElementType();
-                    uint64_t AllocSize = TD->getTypeAllocSize(ElTy);
-                    APInt PSA(L->getValue().getBitWidth(), AllocSize);
-                    if (ElTy == cast<PointerType>(DestTy)->getElementType() &&
-                        L->getValue().urem(PSA) == 0) {
-                      APInt ElemIdx = L->getValue().udiv(PSA);
-                      if (ElemIdx.ult(APInt(ElemIdx.getBitWidth(),
-                                            AT->getNumElements()))) {
-                        Constant *Index[] = {
-                          Constant::getNullValue(CE->getType()),
-                          ConstantInt::get(ElTy->getContext(), ElemIdx)
-                        };
-                        return ConstantExpr::getGetElementPtr(GV, &Index[0], 2);
-                      }
-                    }
-                  }
-                }
-      }
-    }
+          TD->getPointerSizeInBits() <= CE->getType()->getScalarSizeInBits() &&
+          CE->getOpcode() == Instruction::PtrToInt)
+        return FoldBitCast(CE->getOperand(0), DestTy, *TD);
+
     return ConstantExpr::getCast(Opcode, Ops[0], DestTy);
   case Instruction::Trunc:
   case Instruction::ZExt:

Removed: llvm/trunk/test/Transforms/InstCombine/constant-fold-ptr-casts.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/constant-fold-ptr-casts.ll?rev=96949&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/constant-fold-ptr-casts.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/constant-fold-ptr-casts.ll (removed)
@@ -1,27 +0,0 @@
-; RUN: opt < %s -instcombine -S | grep {ret i32 2143034560} | count 2
-
-; Instcombine should be able to completely fold this code.
-
-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-f80:128:128"
-target triple = "i686-apple-darwin8"
-
- at bar = constant [3 x i64] [i64 9220983451228067448, i64 9220983451228067449, i64 9220983450959631991], align 8
-
-define i32 @foo() nounwind {
-entry:
-	%tmp87.2 = load i64* inttoptr (i32 add (i32 16, i32 ptrtoint ([3 x i64]* @bar to i32)) to i64*), align 8
-	%t0 = bitcast i64 %tmp87.2 to double
-	%tmp9192.2 = fptrunc double %t0 to float
-	%t1 = bitcast float %tmp9192.2 to i32
-	ret i32 %t1
-}
-
-define i32 @goo() nounwind {
-entry:
-	%tmp87.2 = load i64* inttoptr (i32 add (i32 ptrtoint ([3 x i64]* @bar to i32), i32 16) to i64*), align 8
-	%t0 = bitcast i64 %tmp87.2 to double
-	%tmp9192.2 = fptrunc double %t0 to float
-	%t1 = bitcast float %tmp9192.2 to i32
-	ret i32 %t1
-}
-