[arm-fast-isel] Add support for fastcc.

Without fastcc support, the caller just falls through to CallingConv::C
for fastcc, but callee still uses fastcc, this inconsistency of calling
convention is a problem, and fastcc support can fix it.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162013 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 72 insertions, 3 deletions

diff --git a/lib/Target/ARM/ARMFastISel.cpp b/lib/Target/ARM/ARMFastISel.cpp
index 57f8116039..bf9d16eea1 100644
--- a/lib/Target/ARM/ARMFastISel.cpp
+++ b/lib/Target/ARM/ARMFastISel.cpp
@@ -1821,9 +1821,12 @@ CCAssignFn *ARMFastISel::CCAssignFnForCall(CallingConv::ID CC,
   default:
     llvm_unreachable("Unsupported calling convention");
   case CallingConv::Fast:
-    // Ignore fastcc. Silence compiler warnings.
-    (void)RetFastCC_ARM_APCS;
-    (void)FastCC_ARM_APCS;
+    if (Subtarget->hasVFP2() && !isVarArg) {
+      if (!Subtarget->isAAPCS_ABI())
+        return (Return ? RetFastCC_ARM_APCS : FastCC_ARM_APCS);
+      // For AAPCS ABI targets, just use VFP variant of the calling convention.
+      return (Return ? RetCC_ARM_AAPCS_VFP : CC_ARM_AAPCS_VFP);
+    }
     // Fallthrough
   case CallingConv::C:
     // Use target triple & subtarget features to do actual dispatch.
diff --git a/test/CodeGen/ARM/fast-isel-call.ll b/test/CodeGen/ARM/fast-isel-call.ll
index edc805a47d..b6c9098613 100644
--- a/test/CodeGen/ARM/fast-isel-call.ll
+++ b/test/CodeGen/ARM/fast-isel-call.ll
@@ -2,6 +2,8 @@
 ; RUN: llc < %s -O0 -fast-isel-abort -relocation-model=dynamic-no-pic -mtriple=thumbv7-apple-ios | FileCheck %s --check-prefix=THUMB
 ; RUN: llc < %s -O0 -fast-isel-abort -relocation-model=dynamic-no-pic -mtriple=armv7-apple-ios -arm-long-calls | FileCheck %s --check-prefix=ARM-LONG
 ; RUN: llc < %s -O0 -fast-isel-abort -relocation-model=dynamic-no-pic -mtriple=thumbv7-apple-ios -arm-long-calls | FileCheck %s --check-prefix=THUMB-LONG
+; RUN: llc < %s -O0 -relocation-model=dynamic-no-pic -mtriple=armv7-apple-ios -mattr=-vfp2 | FileCheck %s --check-prefix=ARM-NOVFP
+; RUN: llc < %s -O0 -relocation-model=dynamic-no-pic -mtriple=thumbv7-apple-ios -mattr=-vfp2 | FileCheck %s --check-prefix=THUMB-NOVFP
 
 define i32 @t0(i1 zeroext %a) nounwind {
   %1 = zext i1 %a to i32
@@ -221,3 +223,67 @@ entry:
 }
 
 declare i32 @CallVariadic(i32, ...)
+
+; Test fastcc
+
+define fastcc void @fast_callee(float %i) ssp {
+entry:
+; ARM: fast_callee
+; ARM: vmov r0, s0
+; THUMB: fast_callee
+; THUMB: vmov r0, s0
+; ARM-NOVFP: fast_callee
+; ARM-NOVFP-NOT: s0
+; THUMB-NOVFP: fast_callee
+; THUMB-NOVFP-NOT: s0
+  call void @print(float %i)
+  ret void
+}
+
+define void @fast_caller() ssp {
+entry:
+; ARM: fast_caller
+; ARM: vldr s0,
+; THUMB: fast_caller
+; THUMB: vldr s0,
+; ARM-NOVFP: fast_caller
+; ARM-NOVFP: movw r0, #13107
+; ARM-NOVFP: movt r0, #16611
+; THUMB-NOVFP: fast_caller
+; THUMB-NOVFP: movw r0, #13107
+; THUMB-NOVFP: movt r0, #16611
+  call fastcc void @fast_callee(float 0x401C666660000000)
+  ret void
+}
+
+define void @no_fast_callee(float %i) ssp {
+entry:
+; ARM: no_fast_callee
+; ARM: vmov s0, r0
+; THUMB: no_fast_callee
+; THUMB: vmov s0, r0
+; ARM-NOVFP: no_fast_callee
+; ARM-NOVFP-NOT: s0
+; THUMB-NOVFP: no_fast_callee
+; THUMB-NOVFP-NOT: s0
+  call void @print(float %i)
+  ret void
+}
+
+define void @no_fast_caller() ssp {
+entry:
+; ARM: no_fast_caller
+; ARM: vmov r0, s0
+; THUMB: no_fast_caller
+; THUMB: vmov r0, s0
+; ARM-NOVFP: no_fast_caller
+; ARM-NOVFP: movw r0, #13107
+; ARM-NOVFP: movt r0, #16611
+; THUMB-NOVFP: no_fast_caller
+; THUMB-NOVFP: movw r0, #13107
+; THUMB-NOVFP: movt r0, #16611
+  call void @no_fast_callee(float 0x401C666660000000)
+  ret void
+}
+
+declare void @print(float)