The SPARCv9 ABI returns a float in %f0.

This is different from the argument passing convention which puts the
first float argument in %f1.

With this patch, all returned floats are treated as if the 'inreg' flag
were set. This means multiple float return values get packed in %f0,
%f1, %f2, ...

Note that when returning a struct in registers, clang will set the
'inreg' flag on the return value, so that behavior is unchanged. This
also happens when returning a float _Complex.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199028 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 10 insertions, 1 deletions

diff --git a/lib/Target/Sparc/SparcCallingConv.td b/lib/Target/Sparc/SparcCallingConv.td
index acd4ec21de..dfaaabf344 100644
--- a/lib/Target/Sparc/SparcCallingConv.td
+++ b/lib/Target/Sparc/SparcCallingConv.td
@@ -103,7 +103,7 @@ def RetCC_Sparc32 : CallingConv<[
 // Function return values are passed exactly like function arguments, except a
 // struct up to 32 bytes in size can be returned in registers.
 
-// Function arguments AND return values.
+// Function arguments AND most return values.
 def CC_Sparc64 : CallingConv<[
   // The frontend uses the inreg flag to indicate i32 and float arguments from
   // structs. These arguments are not promoted to 64 bits, but they can still
@@ -118,6 +118,15 @@ def CC_Sparc64 : CallingConv<[
   CCCustom<"CC_Sparc64_Full">
 ]>;
 
+def RetCC_Sparc64 : CallingConv<[
+  // A single f32 return value always goes in %f0. The ABI doesn't specify what
+  // happens to multiple f32 return values outside a struct.
+  CCIfType<[f32], CCCustom<"CC_Sparc64_Half">>,
+
+  // Otherwise, return values are passed exactly like arguments.
+  CCDelegateTo<CC_Sparc64>
+]>;
+
 // Callee-saved registers are handled by the register window mechanism.
 def CSR : CalleeSavedRegs<(add)> {
   let OtherPreserved = (add (sequence "I%u", 0, 7),