[AIX] Let alloca return 16 bytes alignment

[Xiangling_L]

Summary

On AIX, to support vector types, which should always be 16bytes aligned, we set alloca to return 16 bytes aligned memory space.

[hubert.reinterpretcast]

clang/test/CodeGen/aix_alloca_align.c

2

Minor nit: Use double-hyphen for long option and = instead of space between the option and the argument.

5

Same comment.

7

Minor comment: Use __SIZE_TYPE__.

[Xiangling_L]

Fixed the testcase formatting issues;
Fixed the BIGGEST_ALIGNMENT value in testcases;

[hubert.reinterpretcast]

clang/test/CodeGen/aix_alloca_align.c

12

I'm not entirely sure, but can we try for size 32 and see if we get 16?

[Xiangling_L]

clang/test/CodeGen/aix_alloca_align.c

12

Sure, I will add this in.

[Xiangling_L]

Add one case to the test;

[hubert.reinterpretcast]

LGTM; thanks!

clang/lib/Basic/Targets/PPC.h

case llvm::Triple::NetBSD:
       SizeType = UnsignedInt;
       PtrDiffType = SignedInt;
       IntPtrType = SignedInt;
       break;
     case llvm::Triple::AIX:
       SizeType = UnsignedLong;
       PtrDiffType = SignedLong;
       IntPtrType = SignedLong;
-      SuitableAlign = 64;
       LongDoubleWidth = 64;
       LongDoubleAlign = DoubleAlign = 32;
       LongDoubleFormat = &llvm::APFloat::IEEEdouble();
       break;
     default:
       break;
     }
 
PPC64TargetInfo(const llvm::Triple &Triple, const TargetOptions &Opts)
     LongWidth = LongAlign = PointerWidth = PointerAlign = 64;
     IntMaxType = SignedLong;
     Int64Type = SignedLong;
     std::string DataLayout = "";
 
     if (Triple.isOSAIX()) {
       // TODO: Set appropriate ABI for AIX platform.
       DataLayout = "E-m:a-i64:64-n32:64";
-      SuitableAlign = 64;
       LongDoubleWidth = 64;
       LongDoubleAlign = DoubleAlign = 32;
       LongDoubleFormat = &llvm::APFloat::IEEEdouble();
     } else if ((Triple.getArch() == llvm::Triple::ppc64le)) {
       DataLayout = "e-m:e-i64:64-n32:64";
       ABI = "elfv2";
     } else {
       DataLayout = "E-m:e-i64:64-n32:64";

clang/test/CodeGen/aix_alloca_align.c

+// RUN: %clang_cc1 -triple=powerpc-ibm-aix-xcoff -S -emit-llvm < %s | \
+// RUN:   FileCheck -check-prefix 32BIT %s
+
+// RUN: %clang_cc1 -triple=powerpc64-ibm-aix-xcoff -S -emit-llvm < %s | \
+// RUN:   FileCheck -check-prefix 64BIT %s
+
+typedef long unsigned int size_t;
+extern void *alloca(size_t __size) __attribute__((__nothrow__));
+
+void foo() {
+  char *ptr1 = (char *)alloca(sizeof(char) * 9);
+}
+
+// 32BIT: %0 = alloca i8, i32 9, align 16
+// 64BIT: %0 = alloca i8, i64 9, align 16