Revert r347417 "Re-Reinstate 347294 with a fix for the failures."

This caused a miscompile in Chrome (see crbug.com/908372) that's
illustrated by this small reduction:

  static bool f(int *a, int *b) {
    return !__builtin_constant_p(b - a) || (!(b - a));
  }

  int arr[] = {1,2,3};

  bool g() {
    return f(arr, arr + 3);
  }

  $ clang -O2 -S -emit-llvm a.cc -o -

g() should return true, but after r347417 it became false for some reason.

This also reverts the follow-up commits.

r347417:
> Re-Reinstate 347294 with a fix for the failures.
>
> Don't try to emit a scalar expression for a non-scalar argument to
> __builtin_constant_p().
>
> Third time's a charm!

r347446:
> The result of is.constant() is unsigned.

r347480:
> A __builtin_constant_p() returns 0 with a function type.

r347512:
> isEvaluatable() implies a constant context.
>
> Assume that we're in a constant context if we're asking if the expression can
> be compiled into a constant initializer. This fixes the issue where a
> __builtin_constant_p() in a compound literal was diagnosed as not being
> constant, even though it's always possible to convert the builtin into a
> constant.

r347531:
> A "constexpr" is evaluated in a constant context. Make sure this is reflected
> if a __builtin_constant_p() is a part of a constexpr.

llvm-svn: 347656

1 files changed, 0 insertions, 159 deletions

diff --git a/clang/test/CodeGen/builtin-constant-p.c b/clang/test/CodeGen/builtin-constant-p.c
deleted file mode 100644
index 5cdcc721235..00000000000
--- a/clang/test/CodeGen/builtin-constant-p.c
+++ /dev/null
@@ -1,159 +0,0 @@
-// RUN: %clang_cc1 -triple x86_64-unknown-unknown -emit-llvm -o - %s -O2 | FileCheck %s
-
-int a = 42;
-
-inline int bcp(int x) {
-  return __builtin_constant_p(x);
-}
-
-/* --- Compound literals */
-
-struct foo { int x, y; };
-
-int y;
-struct foo f = (struct foo){ __builtin_constant_p(y), 42 };
-
-struct foo test0(int expr) {
-  // CHECK: define i64 @test0(i32 %expr)
-  // CHECK: call i1 @llvm.is.constant.i32(i32 %expr)
-  struct foo f = (struct foo){ __builtin_constant_p(expr), 42 };
-  return f;
-}
-
-/* --- Pointer types */
-
-inline int test1_i(int *x) {
-  return *x;
-}
-
-int test1() {
-  // CHECK: define i32 @test1
-  // CHECK: add nsw i32 %0, -13
-  // CHECK-NEXT: call i1 @llvm.is.constant.i32(i32 %sub)
-  return bcp(test1_i(&a) - 13);
-}
-
-int test2() {
-  // CHECK: define i32 @test2
-  // CHECK: ret i32 0
-  return __builtin_constant_p(&a - 13);
-}
-
-inline int test3_i(int *x) {
-  return 42;
-}
-
-int test3() {
-  // CHECK: define i32 @test3
-  // CHECK: ret i32 1
-  return bcp(test3_i(&a) - 13);
-}
-
-/* --- Aggregate types */
-
-int b[] = {1, 2, 3};
-
-int test4() {
-  // CHECK: define i32 @test4
-  // CHECK: ret i32 0
-  return __builtin_constant_p(b);
-}
-
-const char test5_c[] = {1, 2, 3, 0};
-
-int test5() {
-  // CHECK: define i32 @test5
-  // CHECK: ret i32 0
-  return __builtin_constant_p(test5_c);
-}
-
-inline char test6_i(const char *x) {
-  return x[1];
-}
-
-int test6() {
-  // CHECK: define i32 @test6
-  // CHECK: ret i32 0
-  return __builtin_constant_p(test6_i(test5_c));
-}
-
-/* --- Non-constant global variables */
-
-int test7() {
-  // CHECK: define i32 @test7
-  // CHECK: call i1 @llvm.is.constant.i32(i32 %0)
-  return bcp(a);
-}
-
-/* --- Constant global variables */
-
-const int c = 42;
-
-int test8() {
-  // CHECK: define i32 @test8
-  // CHECK: ret i32 1
-  return bcp(c);
-}
-
-/* --- Array types */
-
-int arr[] = { 1, 2, 3 };
-const int c_arr[] = { 1, 2, 3 };
-
-int test9() {
-  // CHECK: define i32 @test9
-  // CHECK: call i1 @llvm.is.constant.i32(i32 %0)
-  return __builtin_constant_p(arr[2]);
-}
-
-int test10() {
-  // CHECK: define i32 @test10
-  // CHECK: ret i32 1
-  return __builtin_constant_p(c_arr[2]);
-}
-
-int test11() {
-  // CHECK: define i32 @test11
-  // CHECK: ret i32 0
-  return __builtin_constant_p(c_arr);
-}
-
-/* --- Function pointers */
-
-int test12() {
-  // CHECK: define i32 @test12
-  // CHECK: ret i32 0
-  return __builtin_constant_p(&test10);
-}
-
-int test13() {
-  // CHECK: define i32 @test13
-  // CHECK: ret i32 1
-  return __builtin_constant_p(&test10 != 0);
-}
-
-typedef unsigned long uintptr_t;
-#define assign(p, v) ({ \
-  uintptr_t _r_a_p__v = (uintptr_t)(v);                           \
-  if (__builtin_constant_p(v) && _r_a_p__v == (uintptr_t)0) {     \
-    union {                                                       \
-      uintptr_t __val;                                            \
-      char __c[1];                                                \
-    } __u = {                                                     \
-      .__val = (uintptr_t)_r_a_p__v                               \
-    };                                                            \
-    *(volatile unsigned int*)&p = *(unsigned int*)(__u.__c);      \
-    __u.__val;                                                    \
-  }                                                               \
-  _r_a_p__v;                                                      \
-})
-
-typedef void fn_p(void);
-extern fn_p *dest_p;
-
-static void src_fn(void) {
-}
-
-void test14() {
-  assign(dest_p, src_fn);
-}