This patch solves a problem with passing varargs parameters under the PPC64

ELF ABI.

A varargs parameter consisting of a single-precision floating-point value,
or of a single-element aggregate containing a single-precision floating-point
value, must be passed in the low-order (rightmost) four bytes of the
doubleword stack slot reserved for that parameter.  If there are GPR protocol
registers remaining, the parameter must also be mirrored in the low-order
four bytes of the reserved GPR.

Prior to this patch, such parameters were being passed in the high-order
four bytes of the stack slot and the mirrored GPR.

The patch adds a new test case to verify the correct code generation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166968 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/PowerPC/PPCISelLowering.cpp b/lib/Target/PowerPC/PPCISelLowering.cpp
index cbb043cab807f346378e5e2f932538b878fccef3..f27791013e0010e03c4339fb0e2ba311bf1f9a12 100644 (file)
--- a/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -3751,7 +3751,17 @@ PPCTargetLowering::LowerCall_64SVR4(SDValue Chain, SDValue Callee,
         RegsToPass.push_back(std::make_pair(FPR[FPR_idx++], Arg));
 
         if (isVarArg) {
-          SDValue Store = DAG.getStore(Chain, dl, Arg, PtrOff,
+          // A single float or an aggregate containing only a single float
+          // must be passed right-justified in the stack doubleword, and
+          // in the GPR, if one is available.
+          SDValue StoreOff;
+          if (Arg.getValueType().getSimpleVT().SimpleTy == MVT::f32) {
+            SDValue ConstFour = DAG.getConstant(4, PtrOff.getValueType());
+            StoreOff = DAG.getNode(ISD::ADD, dl, PtrVT, PtrOff, ConstFour);
+          } else
+            StoreOff = PtrOff;
+
+          SDValue Store = DAG.getStore(Chain, dl, Arg, StoreOff,
                                        MachinePointerInfo(), false, false, 0);
           MemOpChains.push_back(Store);
 

diff --git a/test/CodeGen/PowerPC/varargs-struct-float.ll b/test/CodeGen/PowerPC/varargs-struct-float.ll
new file mode 100644 (file)
index 0000000..fb1835f
--- /dev/null
+++ b/test/CodeGen/PowerPC/varargs-struct-float.ll
@@ -0,0 +1,23 @@
+; RUN: llc -mcpu=pwr7 -O0 < %s | FileCheck %s
+
+target datalayout = "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-f128:128:128-v128:128:128-n32:64"
+target triple = "powerpc64-unknown-linux-gnu"
+
+%struct.Sf1 = type { float }
+
+define void @foo(float inreg %s.coerce) nounwind {
+entry:
+  %s = alloca %struct.Sf1, align 4
+  %coerce.dive = getelementptr %struct.Sf1* %s, i32 0, i32 0
+  store float %s.coerce, float* %coerce.dive, align 1
+  %coerce.dive1 = getelementptr %struct.Sf1* %s, i32 0, i32 0
+  %0 = load float* %coerce.dive1, align 1
+  call void (i32, ...)* @testvaSf1(i32 1, float inreg %0)
+  ret void
+}
+
+; CHECK: stfs {{[0-9]+}}, 60(1)
+; CHECK: ld 4, 56(1)
+; CHECK: bl
+
+declare void @testvaSf1(i32, ...)