This patch addresses PR13947.

For function calls on the 64-bit PowerPC SVR4 target, each parameter
is mapped to as many doublewords in the parameter save area as
necessary to hold the parameter.  The first 13 non-varargs
floating-point values are passed in registers; any additional
floating-point parameters are passed in the parameter save area.  A
single-precision floating-point parameter (32 bits) must be mapped to
the second (rightmost, low-order) word of its assigned doubleword
slot.

Currently LLVM violates this ABI requirement by mapping such a
parameter to the first (leftmost, high-order) word of its assigned
doubleword slot.  This is internally self-consistent but will not
interoperate correctly with libraries compiled with an ABI-compliant
compiler.

This patch corrects the problem by adjusting the parameter addressing
on both sides of the calling convention.

llvm-svn: 165714

1 files changed, 8 insertions, 0 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
index 64bbcdfa94e..660bfb45f82 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -2142,6 +2142,7 @@ PPCTargetLowering::LowerFormalArguments_64SVR4(
         ++FPR_idx;
       } else {
         needsLoad = true;
+        ArgSize = PtrByteSize;
       }
 
       ArgOffset += 8;
@@ -3786,6 +3787,13 @@ PPCTargetLowering::LowerCall_Darwin_Or_64SVR4(SDValue Chain, SDValue Callee,
             ++GPR_idx;
         }
       } else {
+        // Single-precision floating-point values are mapped to the
+        // second (rightmost) word of the stack doubleword.
+        if (Arg.getValueType() == MVT::f32 && isPPC64 && isSVR4ABI) {
+          SDValue ConstFour = DAG.getConstant(4, PtrOff.getValueType());
+          PtrOff = DAG.getNode(ISD::ADD, dl, PtrVT, PtrOff, ConstFour);
+        }
+
         LowerMemOpCallTo(DAG, MF, Chain, Arg, PtrOff, SPDiff, ArgOffset,
                          isPPC64, isTailCall, false, MemOpChains,
                          TailCallArguments, dl);