[PATCH] ARM: __gnu_h2f_ieee and __gnu_f2h_ieee always use the soft-float calling convention

[Anton Korobeynikov]

LGTM

On Fri, Aug 8, 2014 at 6:16 PM, Oliver Stannard <oliver.stannard at arm.com> wrote:
> By default, LLVM uses the "C" calling convention for all runtime library functions. The half-precision FP conversion functions use the soft-float calling convention, and are needed for some targets which use the hard-float convention by default, so must have their calling convention explicitly set.
>
> http://reviews.llvm.org/D4830
>
> Files:
>   lib/Target/ARM/ARMISelLowering.cpp
>   test/CodeGen/ARM/fp16.ll
>
> Index: lib/Target/ARM/ARMISelLowering.cpp
> ===================================================================
> --- lib/Target/ARM/ARMISelLowering.cpp
> +++ lib/Target/ARM/ARMISelLowering.cpp
> @@ -388,6 +388,19 @@
>      setLibcallName(RTLIB::UDIVREM_I32, "__udivmodsi4");
>    }
>
> +  // The half <-> float conversion functions are always soft-float, but are
> +  // needed for some targets which use a hard-float calling convention by
> +  // default.
> +  if (Subtarget->isAAPCS_ABI()) {
> +    setLibcallCallingConv(RTLIB::FPROUND_F32_F16, CallingConv::ARM_AAPCS);
> +    setLibcallCallingConv(RTLIB::FPROUND_F64_F16, CallingConv::ARM_AAPCS);
> +    setLibcallCallingConv(RTLIB::FPEXT_F16_F32, CallingConv::ARM_AAPCS);
> +  } else {
> +    setLibcallCallingConv(RTLIB::FPROUND_F32_F16, CallingConv::ARM_APCS);
> +    setLibcallCallingConv(RTLIB::FPROUND_F64_F16, CallingConv::ARM_APCS);
> +    setLibcallCallingConv(RTLIB::FPEXT_F16_F32, CallingConv::ARM_APCS);
> +  }
> +
>    if (Subtarget->isThumb1Only())
>      addRegisterClass(MVT::i32, &ARM::tGPRRegClass);
>    else
> Index: test/CodeGen/ARM/fp16.ll
> ===================================================================
> --- test/CodeGen/ARM/fp16.ll
> +++ test/CodeGen/ARM/fp16.ll
> @@ -1,16 +1,16 @@
>  ; RUN: llc < %s | FileCheck %s
>  ; RUN: llc -mattr=+vfp3,+fp16 < %s | FileCheck --check-prefix=CHECK-FP16 %s
> -; RUN: llc -mtriple=armv8-eabi < %s | FileCheck --check-prefix=CHECK-ARMV8 %s
> +; RUN: llc -mtriple=armv8-eabihf < %s | FileCheck --check-prefix=CHECK-ARMV8 %s
>  ; RUN: llc -mtriple=thumbv7m-eabi < %s | FileCheck --check-prefix=CHECK-SOFTFLOAT %s
>
>  target datalayout = "e-p:32:32:32-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-n32"
> -target triple = "armv7-eabi"
> +target triple = "armv7---eabihf"
>
>  @x = global i16 12902
>  @y = global i16 0
>  @z = common global i16 0
>
> -define arm_aapcs_vfpcc void @foo() nounwind {
> +define void @foo() nounwind {
>  ; CHECK-LABEL: foo:
>  ; CHECK-FP16-LABEL: foo:
>  ; CHECK-ARMV8-LABEL: foo:
> @@ -38,9 +38,9 @@
>    ret void
>  }
>
> -define arm_aapcs_vfpcc double @test_from_fp16(i16 %in) {
> +define double @test_from_fp16(i16 %in) {
>  ; CHECK-LABEL: test_from_fp16:
> -; CHECK-FP-LABEL: test_from_fp16:
> +; CHECK-FP16-LABEL: test_from_fp16:
>  ; CHECK-ARMV8-LABEL: test_from_fp16:
>  ; CHECK-SOFTFLOAT-LABEL: test_from_fp16:
>    %val = call double @llvm.convert.from.fp16.f64(i16 %in)
> @@ -60,15 +60,15 @@
>    ret double %val
>  }
>
> -define arm_aapcs_vfpcc i16 @test_to_fp16(double %in) {
> +define i16 @test_to_fp16(double %in) {
>  ; CHECK-LABEL: test_to_fp16:
> -; CHECK-FP-LABEL: test_to_fp16:
> +; CHECK-FP16-LABEL: test_to_fp16:
>  ; CHECK-ARMV8-LABEL: test_to_fp16:
>  ; CHECK-SOFTFLOAT-LABEL: test_to_fp16:
>    %val = call i16 @llvm.convert.to.fp16.f64(double %in)
> -; CHECK: bl __truncdfhf2
> +; CHECK: bl __aeabi_d2h
>
> -; CHECK-FP16: bl __truncdfhf2
> +; CHECK-FP16: bl __aeabi_d2h
>
>  ; CHECK-ARMV8: vcvtb.f16.f64 [[TMP:s[0-9]+]], d0
>  ; CHECK-ARMV8: vmov r0, [[TMP]]
>
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-- 
With best regards, Anton Korobeynikov
Faculty of Mathematics and Mechanics, Saint Petersburg State University