Enable support for returning two long-double values in ST(0)/ST(1).

This allows us to compile fp-stack-2results.ll into:

_test:
	fldz
	fld1
	ret

which returns 1 in ST(0) and 0 in ST(1).  This is needed for x86-64
_Complex long double.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48632 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 4 insertions, 7 deletions

diff --git a/lib/Target/X86/X86CallingConv.td b/lib/Target/X86/X86CallingConv.td
index 4f25f1f..70f18c5 100644
--- a/lib/Target/X86/X86CallingConv.td
+++ b/lib/Target/X86/X86CallingConv.td
@@ -38,15 +38,15 @@ def RetCC_X86Common : CallingConv<[
   CCIfType<[v8i8, v4i16, v2i32, v1i64], CCAssignToReg<[MM0]>>,
 
   // Long double types are always returned in ST0 (even with SSE).
-  CCIfType<[f80], CCAssignToReg<[ST0]>>
+  CCIfType<[f80], CCAssignToReg<[ST0, ST1]>>
 ]>;
 
 // X86-32 C return-value convention.
 def RetCC_X86_32_C : CallingConv<[
   // The X86-32 calling convention returns FP values in ST0, otherwise it is the
   // same as the common X86 calling conv.
-  CCIfType<[f32], CCAssignToReg<[ST0]>>,
-  CCIfType<[f64], CCAssignToReg<[ST0]>>,
+  CCIfType<[f32], CCAssignToReg<[ST0, ST1]>>,
+  CCIfType<[f64], CCAssignToReg<[ST0, ST1]>>,
   CCDelegateTo<RetCC_X86Common>
 ]>;
 
diff --git a/lib/Target/X86/X86FloatingPoint.cpp b/lib/Target/X86/X86FloatingPoint.cpp
index ca96537..d9ab1ed 100644
--- a/lib/Target/X86/X86FloatingPoint.cpp
+++ b/lib/Target/X86/X86FloatingPoint.cpp
@@ -1053,9 +1053,6 @@ void FPS::handleSpecialFP(MachineBasicBlock::iterator &I) {
       return;
     }
     
-    assert(0 && "TODO: This code should work, but has never been tested."
-           "Test it when we have multiple FP return values working");
-    
     // Otherwise, we are returning two values:
     // 2) If returning the same value for both, we only have one thing in the FP
     //    stack.  Consider:  RET FP1, FP1
@@ -1083,7 +1080,7 @@ void FPS::handleSpecialFP(MachineBasicBlock::iterator &I) {
     /// 4) Finally, FirstFPRegOp must be in ST(0) and SecondFPRegOp must be in
     /// ST(1).  Just remove both from our understanding of the stack and return.
     assert(getStackEntry(0) == FirstFPRegOp && "Unknown regs live");
-    assert(getStackEntry(0) == SecondFPRegOp && "Unknown regs live");
+    assert(getStackEntry(1) == SecondFPRegOp && "Unknown regs live");
     StackTop = 0;
     return;
   }