[FastISel][x86] Teach how to select SSE2/AVX bitcasts between 128/256-bit vector types.

This patch teaches FastIsel the following two things:
1) On SSE2, no instructions are needed for bitcasts between 128-bit vector types;
2) On AVX, no instructions are needed for bitcasts between 256-bit vector types.

Example:

  %1 = bitcast <4 x i31> %V to <2 x i64>

Before (-fast-isel -fast-isel-abort=1):

  FastIsel miss: %1 = bitcast <4 x i31> %V to <2 x i64>

Now we don't fall back to SelectionDAG and we correctly fold that computation
propagating the register associated to %V.

Differential Revision: http://reviews.llvm.org/D13347

llvm-svn: 249121
This commit is contained in:
Andrea Di Biagio 2015-10-02 12:45:37 +00:00
parent b285e9e0d2
commit cb33456122
3 changed files with 513 additions and 0 deletions

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@ -3234,6 +3234,30 @@ X86FastISel::fastSelectInstruction(const Instruction *I) {
updateValueMap(I, Reg);
return true;
}
case Instruction::BitCast: {
// Select SSE2/AVX bitcasts between 128/256 bit vector types.
if (!Subtarget->hasSSE2())
return false;
EVT SrcVT = TLI.getValueType(DL, I->getOperand(0)->getType());
EVT DstVT = TLI.getValueType(DL, I->getType());
if (!SrcVT.isSimple() || !DstVT.isSimple())
return false;
if (!SrcVT.is128BitVector() &&
!(Subtarget->hasAVX() && SrcVT.is256BitVector()))
return false;
unsigned Reg = getRegForValue(I->getOperand(0));
if (Reg == 0)
return false;
// No instruction is needed for conversion. Reuse the register used by
// the fist operand.
updateValueMap(I, Reg);
return true;
}
}
return false;

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@ -0,0 +1,244 @@
; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=+avx -fast-isel -fast-isel-abort=1 -asm-verbose=0 | FileCheck %s
;
; Bitcasts between 256-bit vector types are no-ops since no instruction is
; needed for the conversion.
define <4 x i64> @v8i32_to_v4i64(<8 x i32> %a) {
;CHECK-LABEL: v8i32_to_v4i64:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <8 x i32> %a to <4 x i64>
ret <4 x i64> %1
}
define <4 x i64> @v16i16_to_v4i64(<16 x i16> %a) {
;CHECK-LABEL: v16i16_to_v4i64:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <16 x i16> %a to <4 x i64>
ret <4 x i64> %1
}
define <4 x i64> @v32i8_to_v4i64(<32 x i8> %a) {
;CHECK-LABEL: v32i8_to_v4i64:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <32 x i8> %a to <4 x i64>
ret <4 x i64> %1
}
define <4 x i64> @v4f64_to_v4i64(<4 x double> %a) {
;CHECK-LABEL: v4f64_to_v4i64:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <4 x double> %a to <4 x i64>
ret <4 x i64> %1
}
define <4 x i64> @v8f32_to_v4i64(<8 x float> %a) {
;CHECK-LABEL: v8f32_to_v4i64:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <8 x float> %a to <4 x i64>
ret <4 x i64> %1
}
define <8 x i32> @v4i64_to_v8i32(<4 x i64> %a) {
;CHECK-LABEL: v4i64_to_v8i32:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <4 x i64> %a to <8 x i32>
ret <8 x i32> %1
}
define <8 x i32> @v16i16_to_v8i32(<16 x i16> %a) {
;CHECK-LABEL: v16i16_to_v8i32:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <16 x i16> %a to <8 x i32>
ret <8 x i32> %1
}
define <8 x i32> @v32i8_to_v8i32(<32 x i8> %a) {
;CHECK-LABEL: v32i8_to_v8i32:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <32 x i8> %a to <8 x i32>
ret <8 x i32> %1
}
define <8 x i32> @v4f64_to_v8i32(<4 x double> %a) {
;CHECK-LABEL: v4f64_to_v8i32:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <4 x double> %a to <8 x i32>
ret <8 x i32> %1
}
define <8 x i32> @v8f32_to_v8i32(<8 x float> %a) {
;CHECK-LABEL: v8f32_to_v8i32:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <8 x float> %a to <8 x i32>
ret <8 x i32> %1
}
define <16 x i16> @v4i64_to_v16i16(<4 x i64> %a) {
;CHECK-LABEL: v4i64_to_v16i16:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <4 x i64> %a to <16 x i16>
ret <16 x i16> %1
}
define <16 x i16> @v8i32_to_v16i16(<8 x i32> %a) {
;CHECK-LABEL: v8i32_to_v16i16:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <8 x i32> %a to <16 x i16>
ret <16 x i16> %1
}
define <16 x i16> @v32i8_to_v16i16(<32 x i8> %a) {
;CHECK-LABEL: v32i8_to_v16i16:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <32 x i8> %a to <16 x i16>
ret <16 x i16> %1
}
define <16 x i16> @v4f64_to_v16i16(<4 x double> %a) {
;CHECK-LABEL: v4f64_to_v16i16:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <4 x double> %a to <16 x i16>
ret <16 x i16> %1
}
define <16 x i16> @v8f32_to_v16i16(<8 x float> %a) {
;CHECK-LABEL: v8f32_to_v16i16:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <8 x float> %a to <16 x i16>
ret <16 x i16> %1
}
define <32 x i8> @v16i16_to_v32i8(<16 x i16> %a) {
;CHECK-LABEL: v16i16_to_v32i8:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <16 x i16> %a to <32 x i8>
ret <32 x i8> %1
}
define <32 x i8> @v4i64_to_v32i8(<4 x i64> %a) {
;CHECK-LABEL: v4i64_to_v32i8:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <4 x i64> %a to <32 x i8>
ret <32 x i8> %1
}
define <32 x i8> @v8i32_to_v32i8(<8 x i32> %a) {
;CHECK-LABEL: v8i32_to_v32i8:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <8 x i32> %a to <32 x i8>
ret <32 x i8> %1
}
define <32 x i8> @v4f64_to_v32i8(<4 x double> %a) {
;CHECK-LABEL: v4f64_to_v32i8:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <4 x double> %a to <32 x i8>
ret <32 x i8> %1
}
define <32 x i8> @v8f32_to_v32i8(<8 x float> %a) {
;CHECK-LABEL: v8f32_to_v32i8:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <8 x float> %a to <32 x i8>
ret <32 x i8> %1
}
define <8 x float> @v32i8_to_v8f32(<32 x i8> %a) {
;CHECK-LABEL: v32i8_to_v8f32:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <32 x i8> %a to <8 x float>
ret <8 x float> %1
}
define <8 x float> @v16i16_to_v8f32(<16 x i16> %a) {
;CHECK-LABEL: v16i16_to_v8f32:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <16 x i16> %a to <8 x float>
ret <8 x float> %1
}
define <8 x float> @v4i64_to_v8f32(<4 x i64> %a) {
;CHECK-LABEL: v4i64_to_v8f32:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <4 x i64> %a to <8 x float>
ret <8 x float> %1
}
define <8 x float> @v8i32_to_v8f32(<8 x i32> %a) {
;CHECK-LABEL: v8i32_to_v8f32:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <8 x i32> %a to <8 x float>
ret <8 x float> %1
}
define <8 x float> @v4f64_to_v8f32(<4 x double> %a) {
;CHECK-LABEL: v4f64_to_v8f32:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <4 x double> %a to <8 x float>
ret <8 x float> %1
}
define <4 x double> @v8f32_to_v4f64(<8 x float> %a) {
;CHECK-LABEL: v8f32_to_v4f64:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <8 x float> %a to <4 x double>
ret <4 x double> %1
}
define <4 x double> @v32i8_to_v4f64(<32 x i8> %a) {
;CHECK-LABEL: v32i8_to_v4f64:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <32 x i8> %a to <4 x double>
ret <4 x double> %1
}
define <4 x double> @v16i16_to_v4f64(<16 x i16> %a) {
;CHECK-LABEL: v16i16_to_v4f64:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <16 x i16> %a to <4 x double>
ret <4 x double> %1
}
define <4 x double> @v4i64_to_v4f64(<4 x i64> %a) {
;CHECK-LABEL: v4i64_to_v4f64:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <4 x i64> %a to <4 x double>
ret <4 x double> %1
}
define <4 x double> @v8i32_to_v4f64(<8 x i32> %a) {
;CHECK-LABEL: v8i32_to_v4f64:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <8 x i32> %a to <4 x double>
ret <4 x double> %1
}

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@ -0,0 +1,245 @@
; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=+sse2 -fast-isel -fast-isel-abort=1 -asm-verbose=0 | FileCheck %s
; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=+avx -fast-isel -fast-isel-abort=1 -asm-verbose=0 | FileCheck %s
;
; Bitcasts between 128-bit vector types are no-ops since no instruction is
; needed for the conversion.
define <2 x i64> @v4i32_to_v2i64(<4 x i32> %a) {
;CHECK-LABEL: v4i32_to_v2i64:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <4 x i32> %a to <2 x i64>
ret <2 x i64> %1
}
define <2 x i64> @v8i16_to_v2i64(<8 x i16> %a) {
;CHECK-LABEL: v8i16_to_v2i64:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <8 x i16> %a to <2 x i64>
ret <2 x i64> %1
}
define <2 x i64> @v16i8_to_v2i64(<16 x i8> %a) {
;CHECK-LABEL: v16i8_to_v2i64:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <16 x i8> %a to <2 x i64>
ret <2 x i64> %1
}
define <2 x i64> @v2f64_to_v2i64(<2 x double> %a) {
;CHECK-LABEL: v2f64_to_v2i64:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <2 x double> %a to <2 x i64>
ret <2 x i64> %1
}
define <2 x i64> @v4f32_to_v2i64(<4 x float> %a) {
;CHECK-LABEL: v4f32_to_v2i64:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <4 x float> %a to <2 x i64>
ret <2 x i64> %1
}
define <4 x i32> @v2i64_to_v4i32(<2 x i64> %a) {
;CHECK-LABEL: v2i64_to_v4i32:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <2 x i64> %a to <4 x i32>
ret <4 x i32> %1
}
define <4 x i32> @v8i16_to_v4i32(<8 x i16> %a) {
;CHECK-LABEL: v8i16_to_v4i32:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <8 x i16> %a to <4 x i32>
ret <4 x i32> %1
}
define <4 x i32> @v16i8_to_v4i32(<16 x i8> %a) {
;CHECK-LABEL: v16i8_to_v4i32:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <16 x i8> %a to <4 x i32>
ret <4 x i32> %1
}
define <4 x i32> @v2f64_to_v4i32(<2 x double> %a) {
;CHECK-LABEL: v2f64_to_v4i32:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <2 x double> %a to <4 x i32>
ret <4 x i32> %1
}
define <4 x i32> @v4f32_to_v4i32(<4 x float> %a) {
;CHECK-LABEL: v4f32_to_v4i32:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <4 x float> %a to <4 x i32>
ret <4 x i32> %1
}
define <8 x i16> @v2i64_to_v8i16(<2 x i64> %a) {
;CHECK-LABEL: v2i64_to_v8i16:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <2 x i64> %a to <8 x i16>
ret <8 x i16> %1
}
define <8 x i16> @v4i32_to_v8i16(<4 x i32> %a) {
;CHECK-LABEL: v4i32_to_v8i16:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <4 x i32> %a to <8 x i16>
ret <8 x i16> %1
}
define <8 x i16> @v16i8_to_v8i16(<16 x i8> %a) {
;CHECK-LABEL: v16i8_to_v8i16:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <16 x i8> %a to <8 x i16>
ret <8 x i16> %1
}
define <8 x i16> @v2f64_to_v8i16(<2 x double> %a) {
;CHECK-LABEL: v2f64_to_v8i16:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <2 x double> %a to <8 x i16>
ret <8 x i16> %1
}
define <8 x i16> @v4f32_to_v8i16(<4 x float> %a) {
;CHECK-LABEL: v4f32_to_v8i16:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <4 x float> %a to <8 x i16>
ret <8 x i16> %1
}
define <16 x i8> @v8i16_to_v16i8(<8 x i16> %a) {
;CHECK-LABEL: v8i16_to_v16i8:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <8 x i16> %a to <16 x i8>
ret <16 x i8> %1
}
define <16 x i8> @v2i64_to_v16i8(<2 x i64> %a) {
;CHECK-LABEL: v2i64_to_v16i8:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <2 x i64> %a to <16 x i8>
ret <16 x i8> %1
}
define <16 x i8> @v4i32_to_v16i8(<4 x i32> %a) {
;CHECK-LABEL: v4i32_to_v16i8:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <4 x i32> %a to <16 x i8>
ret <16 x i8> %1
}
define <16 x i8> @v2f64_to_v16i8(<2 x double> %a) {
;CHECK-LABEL: v2f64_to_v16i8:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <2 x double> %a to <16 x i8>
ret <16 x i8> %1
}
define <16 x i8> @v4f32_to_v16i8(<4 x float> %a) {
;CHECK-LABEL: v4f32_to_v16i8:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <4 x float> %a to <16 x i8>
ret <16 x i8> %1
}
define <4 x float> @v16i8_to_v4f32(<16 x i8> %a) {
;CHECK-LABEL: v16i8_to_v4f32:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <16 x i8> %a to <4 x float>
ret <4 x float> %1
}
define <4 x float> @v8i16_to_v4f32(<8 x i16> %a) {
;CHECK-LABEL: v8i16_to_v4f32:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <8 x i16> %a to <4 x float>
ret <4 x float> %1
}
define <4 x float> @v2i64_to_v4f32(<2 x i64> %a) {
;CHECK-LABEL: v2i64_to_v4f32:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <2 x i64> %a to <4 x float>
ret <4 x float> %1
}
define <4 x float> @v4i32_to_v4f32(<4 x i32> %a) {
;CHECK-LABEL: v4i32_to_v4f32:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <4 x i32> %a to <4 x float>
ret <4 x float> %1
}
define <4 x float> @v2f64_to_v4f32(<2 x double> %a) {
;CHECK-LABEL: v2f64_to_v4f32:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <2 x double> %a to <4 x float>
ret <4 x float> %1
}
define <2 x double> @v4f32_to_v2f64(<4 x float> %a) {
;CHECK-LABEL: v4f32_to_v2f64:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <4 x float> %a to <2 x double>
ret <2 x double> %1
}
define <2 x double> @v16i8_to_v2f64(<16 x i8> %a) {
;CHECK-LABEL: v16i8_to_v2f64:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <16 x i8> %a to <2 x double>
ret <2 x double> %1
}
define <2 x double> @v8i16_to_v2f64(<8 x i16> %a) {
;CHECK-LABEL: v8i16_to_v2f64:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <8 x i16> %a to <2 x double>
ret <2 x double> %1
}
define <2 x double> @v2i64_to_v2f64(<2 x i64> %a) {
;CHECK-LABEL: v2i64_to_v2f64:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <2 x i64> %a to <2 x double>
ret <2 x double> %1
}
define <2 x double> @v4i32_to_v2f64(<4 x i32> %a) {
;CHECK-LABEL: v4i32_to_v2f64:
;CHECK-NEXT: .cfi_startproc
;CHECK-NEXT: ret
%1 = bitcast <4 x i32> %a to <2 x double>
ret <2 x double> %1
}