Fix PR15332 (patch by Florian Zeitz).

There's no need to generate a stack frame for PPC32 SVR4 when there are
no local variables assigned to the stack, i.e., when no red zone is needed.
(PPC64 supports a red zone, but PPC32 does not.)



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176124 91177308-0d34-0410-b5e6-96231b3b80d8

test/CodeGen/PowerPC/svr4-redzone.ll

@@ -0,0 +1,39 @@
+; RUN: llc -mtriple="powerpc-unknown-linux-gnu" < %s | FileCheck %s --check-prefix=PPC32
+; RUN: llc -mtriple="powerpc64-unknown-linux-gnu" < %s | FileCheck %s --check-prefix=PPC64
+; PR15332
+
+define void @regalloc() nounwind {
+entry:
+	%0 = add i32 1, 2
+	ret void
+}
+; PPC32: regalloc:
+; PPC32-NOT: stwu 1, -{{[0-9]+}}(1)
+; PPC32: blr
+
+; PPC64: regalloc:
+; PPC64-NOT: stdu 1, -{{[0-9]+}}(1)
+; PPC64: blr
+
+define void @smallstack() nounwind {
+entry:
+	%0 = alloca i8, i32 4
+	ret void
+}
+; PPC32: smallstack:
+; PPC32: stwu 1, -16(1)
+
+; PPC64: smallstack:
+; PPC64-NOT: stdu 1, -{{[0-9]+}}(1)
+; PPC64: blr
+
+define void @bigstack() nounwind {
+entry:
+	%0 = alloca i8, i32 230
+	ret void
+}
+; PPC32: bigstack:
+; PPC32: stwu 1, -240(1)
+
+; PPC64: bigstack:
+; PPC64: stdu 1, -352(1)