This patch adds alignment information for long double to the 64-bit PowerPC

ELF subtarget.

The existing logic is used as a fallback to avoid any changes to the Darwin
ABI.  PPC64 ELF now has two possible data layout strings: one for FreeBSD,
which requires 8-byte alignment, and a default string that requires
16-byte alignment.

I've added a test for PPC64 Linux to verify the 16-byte alignment.  If
somebody wants to add a separate test for FreeBSD, that would be great.

Note that there is a companion patch to update the alignment information
in Clang, which I am committing now as well.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166928 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/PowerPC/PPCSubtarget.h b/lib/Target/PowerPC/PPCSubtarget.h
index c20995afe833063b9760ea4a2bc6b4d2543597f4..77784e045de22e6bfd683932d1ebb4ec051fc4a1 100644 (file)
--- a/lib/Target/PowerPC/PPCSubtarget.h
+++ b/lib/Target/PowerPC/PPCSubtarget.h
@@ -113,6 +113,12 @@ public:
   const char *getDataLayoutString() const {
     // Note, the alignment values for f64 and i64 on ppc64 in Darwin
     // documentation are wrong; these are correct (i.e. "what gcc does").
+    if (isPPC64() && isSVR4ABI())
+      if (TargetTriple.getOS() == llvm::Triple::FreeBSD)
+        return "E-p:64:64-f64:64:64-i64:64:64-f128:64:64-v128:128:128-n32:64";
+      else
+        return "E-p:64:64-f64:64:64-i64:64:64-f128:128:128-v128:128:128-n32:64";
+
     return isPPC64() ? "E-p:64:64-f64:64:64-i64:64:64-f128:64:128-n32:64"
                      : "E-p:32:32-f64:64:64-i64:64:64-f128:64:128-n32";
   }

diff --git a/test/CodeGen/PowerPC/ppc64-align-long-double.ll b/test/CodeGen/PowerPC/ppc64-align-long-double.ll
new file mode 100644 (file)
index 0000000..10b70d0
--- /dev/null
+++ b/test/CodeGen/PowerPC/ppc64-align-long-double.ll
@@ -0,0 +1,26 @@
+; RUN: llc -mcpu=pwr7 -O0 < %s | FileCheck %s
+
+; Verify internal alignment of long double in a struct.  The double
+; argument comes in in GPR3; GPR4 is skipped; GPRs 5 and 6 contain
+; the long double.  Check that these are stored to proper locations
+; in the parameter save area and loaded from there for return in FPR1/2.
+
+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.S = type { double, ppc_fp128 }
+
+define ppc_fp128 @test(%struct.S* byval %x) nounwind {
+entry:
+  %b = getelementptr inbounds %struct.S* %x, i32 0, i32 1
+  %0 = load ppc_fp128* %b, align 16
+  ret ppc_fp128 %0
+}
+
+; CHECK: std 6, 72(1)
+; CHECK: std 5, 64(1)
+; CHECK: std 4, 56(1)
+; CHECK: std 3, 48(1)
+; CHECK: lfd 1, 64(1)
+; CHECK: lfd 2, 72(1)
+