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[X86][FastIsel] Teach how to select float-half conversion intrinsics.
This patch teaches X86FastISel how to select intrinsic 'convert_from_fp16' and intrinsic 'convert_to_fp16'. If the target has F16C, we can select VCVTPS2PHrr for a float-half conversion, and VCVTPH2PSrr for a half-float conversion. Differential Revision: http://reviews.llvm.org/D7673 llvm-svn: 230043
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Andrea Di Biagio
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Andrea Di Biagio
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Feb 20, 2015
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; RUN: llc -fast-isel -fast-isel-abort -mtriple=x86_64-unknown-unknown -mattr=+f16c < %s | ||
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; XFAIL: * | ||
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; In the future, we might want to teach fast-isel how to expand a double-to-half | ||
; conversion into a double-to-float conversion immediately followed by a | ||
; float-to-half conversion. For now, fast-isel is expected to fail. | ||
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define double @test_fp16_to_fp64(i32 %a) { | ||
entry: | ||
%0 = trunc i32 %a to i16 | ||
%1 = call double @llvm.convert.from.fp16.f64(i16 %0) | ||
ret float %0 | ||
} | ||
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define i16 @test_fp64_to_fp16(double %a) { | ||
entry: | ||
%0 = call i16 @llvm.convert.to.fp16.f64(double %a) | ||
ret i16 %0 | ||
} | ||
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declare i16 @llvm.convert.to.fp16.f64(double) | ||
declare double @llvm.convert.from.fp16.f64(i16) |
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; RUN: llc -fast-isel -fast-isel-abort -asm-verbose=false -mtriple=x86_64-unknown-unknown -mattr=+f16c < %s | FileCheck %s | ||
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; Verify that fast-isel correctly expands float-half conversions. | ||
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define i16 @test_fp32_to_fp16(float %a) { | ||
; CHECK-LABEL: test_fp32_to_fp16: | ||
; CHECK: vcvtps2ph $0, %xmm0, %xmm0 | ||
; CHECK-NEXT: vmovd %xmm0, %eax | ||
; CHECK-NEXT: retq | ||
entry: | ||
%0 = call i16 @llvm.convert.to.fp16.f32(float %a) | ||
ret i16 %0 | ||
} | ||
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define float @test_fp16_to_fp32(i32 %a) { | ||
; CHECK-LABEL: test_fp16_to_fp32: | ||
; CHECK: movswl %di, %eax | ||
; CHECK-NEXT: vmovd %eax, %xmm0 | ||
; CHECK-NEXT: vcvtph2ps %xmm0, %xmm0 | ||
; CHECK-NEXT: retq | ||
entry: | ||
%0 = trunc i32 %a to i16 | ||
%1 = call float @llvm.convert.from.fp16.f32(i16 %0) | ||
ret float %1 | ||
} | ||
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declare i16 @llvm.convert.to.fp16.f32(float) | ||
declare float @llvm.convert.from.fp16.f32(i16) |