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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165714 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 97 insertions, 0 deletions

diff --git a/test/CodeGen/PowerPC/floatPSA.ll b/test/CodeGen/PowerPC/floatPSA.ll
new file mode 100644
index 0000000000..b5631a1605
--- /dev/null
+++ b/test/CodeGen/PowerPC/floatPSA.ll
@@ -0,0 +1,97 @@
+; RUN: llc -O0 -mtriple=powerpc64-unknown-linux-gnu < %s | FileCheck %s
+
+; This verifies that single-precision floating point values that can't
+; be passed in registers are stored in the rightmost word of the parameter
+; save area slot.  There are 13 architected floating-point registers, so
+; the 14th is passed in storage.  The address of the 14th argument is
+; 48 (fixed size of the linkage area) + 13 * 8 (first 13 args) + 4
+; (offset to second word) = 156.
+
+define float @bar(float %a, float %b, float %c, float %d, float %e, float %f, float %g, float %h, float %i, float %j, float %k, float %l, float %m, float %n) nounwind {
+entry:
+  %a.addr = alloca float, align 4
+  %b.addr = alloca float, align 4
+  %c.addr = alloca float, align 4
+  %d.addr = alloca float, align 4
+  %e.addr = alloca float, align 4
+  %f.addr = alloca float, align 4
+  %g.addr = alloca float, align 4
+  %h.addr = alloca float, align 4
+  %i.addr = alloca float, align 4
+  %j.addr = alloca float, align 4
+  %k.addr = alloca float, align 4
+  %l.addr = alloca float, align 4
+  %m.addr = alloca float, align 4
+  %n.addr = alloca float, align 4
+  store float %a, float* %a.addr, align 4
+  store float %b, float* %b.addr, align 4
+  store float %c, float* %c.addr, align 4
+  store float %d, float* %d.addr, align 4
+  store float %e, float* %e.addr, align 4
+  store float %f, float* %f.addr, align 4
+  store float %g, float* %g.addr, align 4
+  store float %h, float* %h.addr, align 4
+  store float %i, float* %i.addr, align 4
+  store float %j, float* %j.addr, align 4
+  store float %k, float* %k.addr, align 4
+  store float %l, float* %l.addr, align 4
+  store float %m, float* %m.addr, align 4
+  store float %n, float* %n.addr, align 4
+  %0 = load float* %n.addr, align 4
+  ret float %0
+}
+
+; CHECK: lfs {{[0-9]+}}, 156(1)
+
+define float @foo() nounwind {
+entry:
+  %a = alloca float, align 4
+  %b = alloca float, align 4
+  %c = alloca float, align 4
+  %d = alloca float, align 4
+  %e = alloca float, align 4
+  %f = alloca float, align 4
+  %g = alloca float, align 4
+  %h = alloca float, align 4
+  %i = alloca float, align 4
+  %j = alloca float, align 4
+  %k = alloca float, align 4
+  %l = alloca float, align 4
+  %m = alloca float, align 4
+  %n = alloca float, align 4
+  store float 1.000000e+00, float* %a, align 4
+  store float 2.000000e+00, float* %b, align 4
+  store float 3.000000e+00, float* %c, align 4
+  store float 4.000000e+00, float* %d, align 4
+  store float 5.000000e+00, float* %e, align 4
+  store float 6.000000e+00, float* %f, align 4
+  store float 7.000000e+00, float* %g, align 4
+  store float 8.000000e+00, float* %h, align 4
+  store float 9.000000e+00, float* %i, align 4
+  store float 1.000000e+01, float* %j, align 4
+  store float 1.100000e+01, float* %k, align 4
+  store float 1.200000e+01, float* %l, align 4
+  store float 1.300000e+01, float* %m, align 4
+  store float 1.400000e+01, float* %n, align 4
+  %0 = load float* %a, align 4
+  %1 = load float* %b, align 4
+  %2 = load float* %c, align 4
+  %3 = load float* %d, align 4
+  %4 = load float* %e, align 4
+  %5 = load float* %f, align 4
+  %6 = load float* %g, align 4
+  %7 = load float* %h, align 4
+  %8 = load float* %i, align 4
+  %9 = load float* %j, align 4
+  %10 = load float* %k, align 4
+  %11 = load float* %l, align 4
+  %12 = load float* %m, align 4
+  %13 = load float* %n, align 4
+  %call = call float @bar(float %0, float %1, float %2, float %3, float %4, float %5, float %6, float %7, float %8, float %9, float %10, float %11, float %12, float %13)
+  ret float %call
+}
+
+; Note that stw is used instead of stfs because the value is a simple
+; constant that can be created with a load-immediate in a GPR.
+; CHECK: stw {{[0-9]+}}, 156(1)
+