[llvm-commits] [llvm] r71158 - in /llvm/trunk: lib/Analysis/ConstantFolding.cpp test/Transforms/InstCombine/constant-fold-ptr-casts.ll

[Bill Wendling]

Dan,

This appears to have broken a full bootstrap. Could you investigate
please? See here for details:

http://blamebot.apple.com:8020/builders/full-llvm-OSX/builds/1486/steps/shell/logs/stdio

-bw

On Thu, May 7, 2009 at 7:25 AM, Dan Gohman <gohman at apple.com> wrote:
> Author: djg
> Date: Thu May  7 09:24:56 2009
> New Revision: 71158
>
> URL: http://llvm.org/viewvc/llvm-project?rev=71158&view=rev
> Log:
> Constant-fold ptrtoint+add+inttoptr to gep when the pointer is an
> array and the add is within range. This helps simplify expressions
> expanded by ScalarEvolutionExpander.
>
> Added:
>    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=71158&r1=71157&r2=71158&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/Analysis/ConstantFolding.cpp (original)
> +++ llvm/trunk/lib/Analysis/ConstantFolding.cpp Thu May  7 09:24:56 2009
> @@ -16,6 +16,7 @@
>  #include "llvm/Constants.h"
>  #include "llvm/DerivedTypes.h"
>  #include "llvm/Function.h"
> +#include "llvm/GlobalVariable.h"
>  #include "llvm/Instructions.h"
>  #include "llvm/Intrinsics.h"
>  #include "llvm/ADT/SmallVector.h"
> @@ -383,12 +384,43 @@
>     // 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 (TD && CE->getOpcode() == Instruction::PtrToInt &&
> +      if (TD &&
>           TD->getPointerSizeInBits() <=
>           CE->getType()->getPrimitiveSizeInBits()) {
> -        Constant *Input = CE->getOperand(0);
> -        Constant *C = FoldBitCast(Input, DestTy, *TD);
> -        return C ? C : ConstantExpr::getBitCast(Input, DestTy);
> +        if (CE->getOpcode() == Instruction::PtrToInt) {
> +          Constant *Input = CE->getOperand(0);
> +          Constant *C = FoldBitCast(Input, DestTy, *TD);
> +          return C ? C : ConstantExpr::getBitCast(Input, DestTy);
> +        }
> +        // 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(0)))
> +            if (ConstantExpr *R = dyn_cast<ConstantExpr>(CE->getOperand(1)))
> +              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 PaddedSize = TD->getTypePaddedSize(ElTy);
> +                    APInt PSA(L->getValue().getBitWidth(), PaddedSize);
> +                    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(ElemIdx)
> +                        };
> +                        return ConstantExpr::getGetElementPtr(GV, &Index[0], 2);
> +                      }
> +                    }
> +                  }
> +                }
>       }
>     }
>     return ConstantExpr::getCast(Opcode, Ops[0], DestTy);
>
> Added: 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=71158&view=auto
>
> ==============================================================================
> --- llvm/trunk/test/Transforms/InstCombine/constant-fold-ptr-casts.ll (added)
> +++ llvm/trunk/test/Transforms/InstCombine/constant-fold-ptr-casts.ll Thu May  7 09:24:56 2009
> @@ -0,0 +1,18 @@
> +; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep {ret i32 2143034560}
> +
> +; 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
> +}
> +
>
>
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