[llvm-commits] [llvm] r138206 - in /llvm/trunk: lib/Analysis/ConstantFolding.cpp test/Transforms/InstCombine/bitcast.ll
Duncan Sands
baldrick at free.fr
Sun Aug 21 04:13:38 PDT 2011
Hi Nadav,
> Add constant folding support for bitcasts of splat vectors to integers.
>
>
> Modified:
> llvm/trunk/lib/Analysis/ConstantFolding.cpp
> llvm/trunk/test/Transforms/InstCombine/bitcast.ll
>
> Modified: llvm/trunk/lib/Analysis/ConstantFolding.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ConstantFolding.cpp?rev=138206&r1=138205&r2=138206&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Analysis/ConstantFolding.cpp (original)
> +++ llvm/trunk/lib/Analysis/ConstantFolding.cpp Sat Aug 20 09:02:29 2011
> @@ -46,7 +46,16 @@
> static Constant *FoldBitCast(Constant *C, Type *DestTy,
> const TargetData&TD) {
>
> - // This only handles casts to vectors currently.
> + ConstantVector *CV = dyn_cast<ConstantVector>(C);
> + IntegerType *IntVTy = dyn_cast<IntegerType>(DestTy);
> + // When casting vectors to scalar integers, catch the
> + // obvious splat cases.
> + if (IntVTy&& CV) {
these tests seem fairly pointless. It shouldn't matter that the source is a
vector and the target is an integer. For the null value case you can just do:
if (C->isNullValue())
return Constant::getNullValue(DestTy);
Unfortunately you can't currently do
if (C->isAllOnesValue())
return Constant::getAllOnesValue(DestTy);
That's because isAllOnes value doesn't exist (but I think it should) and
getAllOnes value only handles a limited range of types (but I think it
should be extended to handle everything, like getNullValue). Any chance
of implementing this - making AllOnes work uniformly like NullValue?
Ciao, Duncan.
> + if (CV->isNullValue()) return ConstantInt::getNullValue(IntVTy);
> + if (CV->isAllOnesValue()) return ConstantInt::getAllOnesValue(IntVTy);
> + }
> +
> + // The code below only handles casts to vectors currently.
> VectorType *DestVTy = dyn_cast<VectorType>(DestTy);
> if (DestVTy == 0)
> return ConstantExpr::getBitCast(C, DestTy);
> @@ -59,7 +68,6 @@
> }
>
> // If this is a bitcast from constant vector -> vector, fold it.
> - ConstantVector *CV = dyn_cast<ConstantVector>(C);
> if (CV == 0)
> return ConstantExpr::getBitCast(C, DestTy);
>
>
> Modified: llvm/trunk/test/Transforms/InstCombine/bitcast.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/bitcast.ll?rev=138206&r1=138205&r2=138206&view=diff
> ==============================================================================
> --- llvm/trunk/test/Transforms/InstCombine/bitcast.ll (original)
> +++ llvm/trunk/test/Transforms/InstCombine/bitcast.ll Sat Aug 20 09:02:29 2011
> @@ -1,5 +1,8 @@
> ; RUN: opt< %s -instcombine -S | FileCheck %s
>
> +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-n8:16:32:64"
> +target triple = "x86_64-apple-darwin10.0.0"
> +
> ; Bitcasts between vectors and scalars are valid.
> ; PR4487
> define i32 @test1(i64 %a) {
> @@ -103,3 +106,10 @@
> ; CHECK-NEXT: insertelement<2 x float> <float 4.200000e+01, float undef>, float %A, i32 1
> ; CHECK: ret
> }
> +
> +define i64 @ISPC0(i64 %in) {
> + %out = and i64 %in, xor (i64 bitcast (<4 x i16> <i16 -1, i16 -1, i16 -1, i16 -1> to i64), i64 -1)
> + ret i64 %out
> +; CHECK: @ISPC0
> +; CHECK: ret i64 0
> +}
>
>
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