[ARM] Honor -mfloat-abi for libcall calling convention

[efriedma]

Summary

As far as I can tell, this matches gcc: -mfloat-abi determines the calling convention for all functions except those explicitly defined as soft-float in the ARM RTABI.

This change only affects cases where the user specifies -mfloat-abi to override the default calling convention derived from the target triple.

Fixes https://bugs.llvm.org//show_bug.cgi?id=34530.

(This obsoletes https://reviews.llvm.org/D38050 if it's accepted.)

[peter.smith]

I'm happy with this change; it matches my understanding of what gcc does as well. I think that in practice it is the users responsibility to match the compiler-rt or libgcc with their choice of mfloat-abi.

test/CodeGen/Thumb2/intrinsics-cc.ll

12

Can we remove the CHECK-TO-SOFT and CHECK-TO-HARD --check-prefix as it doesn't look like we have any instances of these any more?

[efriedma]

Fix CHECK lines.

[efriedma]

Ping.

[peter.smith]

I think the change is the right thing to do, I was hoping to see if there were any objections/feedback from anyone that commented more strongly on D38050. If there aren't any more comments by next week I can approve.

[compnerd]

lib/Target/ARM/ARMISelLowering.cpp

234

@peter.smith and I had a look at this. Since at least GCC 4.9, GCC uses the floating point ABI to determine the libcall calling convention. Note that this does break the current ABI.

Given that GCC now does something sane (i.e. only the __aeabi_ functions are soft float, and the other calls are dependent on -mfloat-abi) this seems like the best thing to do.

lib/Target/ARM/ARMISelLowering.cpp

ARMTargetLowering::ARMTargetLowering(const TargetMachine &TM,
   RegInfo = Subtarget->getRegisterInfo();
   Itins = Subtarget->getInstrItineraryData();
 
   setBooleanContents(ZeroOrOneBooleanContent);
   setBooleanVectorContents(ZeroOrNegativeOneBooleanContent);
 
   if (!Subtarget->isTargetDarwin() && !Subtarget->isTargetIOS() &&
       !Subtarget->isTargetWatchOS()) {
-    const auto &E = Subtarget->getTargetTriple().getEnvironment();
-
-    bool IsHFTarget = E == Triple::EABIHF || E == Triple::GNUEABIHF ||
-                      E == Triple::MuslEABIHF;
-    // Windows is a special case.  Technically, we will replace all of the "GNU"
-    // calls with calls to MSVCRT if appropriate and adjust the calling
-    // convention then.
-    IsHFTarget = IsHFTarget || Subtarget->isTargetWindows();
-
+    bool IsHFTarget = TM.Options.FloatABIType == FloatABI::Hard;
     for (int LCID = 0; LCID < RTLIB::UNKNOWN_LIBCALL; ++LCID)
       setLibcallCallingConv(static_cast<RTLIB::Libcall>(LCID),
                             IsHFTarget ? CallingConv::ARM_AAPCS_VFP
                                        : CallingConv::ARM_AAPCS);
   }
 
   if (Subtarget->isTargetMachO()) {
     // Uses VFP for Thumb libfuncs if available.

test/CodeGen/Thumb2/intrinsics-cc.ll

 ; RUN: llc -mtriple thumbv7-unknown-none-eabi -float-abi soft -filetype asm -o - %s | FileCheck %s -check-prefix CHECK-MATCH
 ; RUN: llc -mtriple thumbv7-unknown-none-eabi -float-abi hard -filetype asm -o - %s | FileCheck %s -check-prefix CHECK-MISMATCH -check-prefix CHECK-TO-SOFT
 ; RUN: llc -mtriple thumbv7-unknown-none-eabihf -float-abi soft -filetype asm -o - %s | FileCheck %s -check-prefix CHECK-MISMATCH -check-prefix CHECK-TO-HARD
 ; RUN: llc -mtriple thumbv7-unknown-none-eabihf -float-abi hard -filetype asm -o - %s | FileCheck %s -check-prefix CHECK-MATCH
 
 ; RUN: llc -mtriple thumbv7-unknown-none-gnueabi -float-abi soft -filetype asm -o - %s | FileCheck %s -check-prefix CHECK-MATCH
 ; RUN: llc -mtriple thumbv7-unknown-none-gnueabi -float-abi hard -filetype asm -o - %s | FileCheck %s -check-prefix CHECK-MISMATCH -check-prefix CHECK-TO-SOFT
 ; RUN: llc -mtriple thumbv7-unknown-none-gnueabihf -float-abi soft -filetype asm -o - %s | FileCheck %s -check-prefix CHECK-MISMATCH -check-prefix CHECK-TO-HARD
 ; RUN: llc -mtriple thumbv7-unknown-none-gnueabihf -float-abi hard -filetype asm -o - %s | FileCheck %s -check-prefix CHECK-MATCH
 
 ; RUN: llc -mtriple thumbv7-unknown-none-musleabi -float-abi soft -filetype asm -o - %s | FileCheck %s -check-prefix CHECK-MATCH
 ; RUN: llc -mtriple thumbv7-unknown-none-musleabi -float-abi hard -filetype asm -o - %s | FileCheck %s -check-prefix CHECK-MISMATCH -check-prefix CHECK-TO-SOFT
 ; RUN: llc -mtriple thumbv7-unknown-none-musleabihf -float-abi soft -filetype asm -o - %s | FileCheck %s -check-prefix CHECK-MISMATCH -check-prefix CHECK-TO-HARD
 ; RUN: llc -mtriple thumbv7-unknown-none-musleabihf -float-abi hard -filetype asm -o - %s | FileCheck %s -check-prefix CHECK-MATCH
 
 declare float @llvm.powi.f32(float, i32)
 
-define float @f(float %f, i32 %i) {
+define float @powi_f32(float %f, i32 %i) {
 entry:
   %0 = call float @llvm.powi.f32(float %f, i32 %i)
   ret float %0
 }
 
 ; CHECK-MATCH: b __powisf2
-; CHECK-MISMATCH: bl __powisf2
-; CHECK-TO-SOFT: vmov s0, r0
-; CHECK-TO-HARD: vmov r0, s0
+; CHECK-MISMATCH: b __powisf2
 
 declare double @llvm.powi.f64(double, i32)
 
-define double @g(double %d, i32 %i) {
+define double @powi_f64(double %d, i32 %i) {
 entry:
   %0 = call double @llvm.powi.f64(double %d, i32 %i)
   ret double %0
 }
 
 ; CHECK-MATCH: b __powidf2
-; CHECK-MISMATCH: bl __powidf2
-; CHECK-TO-SOFT: vmov d0, r0, r1
-; CHECK-TO-HARD: vmov r0, r1, d0
+; CHECK-MISMATCH: b __powidf2
 
+declare float @llvm.floor.f32(float)
+
+define float @floor_f32(float %f) {
+entry:
+  %0 = call float @llvm.floor.f32(float %f)
+  ret float %0
+}
+
+; CHECK-MATCH: b floorf
+; CHECK-MISMATCH: b floorf
+
+declare double @llvm.floor.f64(double)
+
+define double @floor_f64(double %d) {
+entry:
+  %0 = call double @llvm.floor.f64(double %d)
+  ret double %0
+}
+
+; CHECK-MATCH: b floor
+; CHECK-MISMATCH: b floor