[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.

llvm-svn: 162013

1 files changed, 6 insertions, 3 deletions

diff --git a/llvm/lib/Target/ARM/ARMFastISel.cpp b/llvm/lib/Target/ARM/ARMFastISel.cpp
index 57f81160394..bf9d16eea18 100644
--- a/llvm/lib/Target/ARM/ARMFastISel.cpp
+++ b/llvm/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.