Avoid output indeterminism between GCC and Clang builds.

Remove dependency of the evalution order of function arguments, which
is unspecified.

The following test previously failed when built with GCC (but succeded
when built with Clang):

  ; RUN: opt -sroa -S < %s | FileCheck %s

  target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
  target triple = "x86_64-unknown-linux-gnu"

  %A = type {i16}

  @a = global %A* null
  @b = global i16 0

  ; CHECK-LABEL: @f1(
  ; CHECK: alloca %A
  ; CHECK-NEXT: extractvalue %A
  ; CHECK-NEXT: getelementptr inbounds %A

  define void @f1 (%A %a) {
    %1 = alloca %A
    store %A %a, %A* %1
    %2 = load i16, i16* @b
    %3 = icmp ne i16 %2, 0
    br i1 %3, label %bb1, label %bb2
  bb1:
    store %A* %1, %A** @a
    br label %bb2
  bb2:
    ret void
  }

Patch by David Stenberg.

Differential Revision: http://reviews.llvm.org/D21226

llvm-svn: 273144