[PATCH][GCC][ARM] Silence more re-definition warnings, make test case failure case more explicit.

[Tamar Christina]

Hi All,

The previous testcase would fail on a system where the initial mode is thumb 
and later
switches to an arm mode. This would again cause some warnings to be emitted.

This patch visits all builtins defined with builtin_define_with_int_value and 
undefines
them if they could possibly change by changing the architecture.

The testcase has also been updated to make it fail more easily on such cases.

Bootstrapped and regtested on arm-none-Linux-gnueabihf and no issues.

Ok for trunk?

Thanks,
Tamar


gcc/
2018-02-07  Tamar Christina  <tamar.christ...@arm.com>

        PR target/82641
        * config/arm/arm-c.c (arm_cpu_builtins): Un-define __ARM_FEATURE_LDREX,
        __ARM_ARCH_PROFILE, __ARM_ARCH_ISA_THUMB, __ARM_FP and __ARM_NEON_FP.

gcc/testsuite
2018-02-07  Tamar Christina  <tamar.christ...@arm.com>

        PR target/82641
        * gcc.target/arm/pragma_arch_switch_2.c: Use armv6 and armv5t.

-- 

diff --git a/gcc/config/arm/arm-c.c b/gcc/config/arm/arm-c.c
index 9a16172f1d8af1a2fb3f24b758650e16ff6e810a..7c741e9fe66a0e086556272a46c4cd709996ce36 100644
--- a/gcc/config/arm/arm-c.c
+++ b/gcc/config/arm/arm-c.c
@@ -87,11 +87,10 @@ arm_cpu_builtins (struct cpp_reader* pfile)
 	builtin_define ("__ARM_FEATURE_CMSE");
     }
 
+  cpp_undef (pfile, "__ARM_FEATURE_LDREX");
   if (TARGET_ARM_FEATURE_LDREX)
     builtin_define_with_int_value ("__ARM_FEATURE_LDREX",
 				   TARGET_ARM_FEATURE_LDREX);
-  else
-    cpp_undef (pfile, "__ARM_FEATURE_LDREX");
 
   def_or_undef_macro (pfile, "__ARM_FEATURE_CLZ",
 		      ((TARGET_ARM_ARCH >= 5 && !TARGET_THUMB)
@@ -105,6 +104,8 @@ arm_cpu_builtins (struct cpp_reader* pfile)
   builtin_define_with_int_value ("__ARM_SIZEOF_MINIMAL_ENUM",
 				 flag_short_enums ? 1 : 4);
   builtin_define_type_sizeof ("__ARM_SIZEOF_WCHAR_T", wchar_type_node);
+
+  cpp_undef (pfile, "__ARM_ARCH_PROFILE");
   if (TARGET_ARM_ARCH_PROFILE)
     builtin_define_with_int_value ("__ARM_ARCH_PROFILE",
 				   TARGET_ARM_ARCH_PROFILE);
@@ -128,6 +129,7 @@ arm_cpu_builtins (struct cpp_reader* pfile)
   else
     def_or_undef_macro (pfile, "__THUMBEL__", TARGET_THUMB);
 
+  cpp_undef (pfile, "__ARM_ARCH_ISA_THUMB");
   if (TARGET_ARM_ARCH_ISA_THUMB)
     builtin_define_with_int_value ("__ARM_ARCH_ISA_THUMB",
 				   TARGET_ARM_ARCH_ISA_THUMB);
@@ -147,10 +149,9 @@ arm_cpu_builtins (struct cpp_reader* pfile)
 
   builtin_define ("__VFP_FP__");
 
+  cpp_undef (pfile, "__ARM_FP");
   if (TARGET_ARM_FP)
     builtin_define_with_int_value ("__ARM_FP", TARGET_ARM_FP);
-  else
-    cpp_undef (pfile, "__ARM_FP");
 
   def_or_undef_macro (pfile, "__ARM_FP16_FORMAT_IEEE",
 		      arm_fp16_format == ARM_FP16_FORMAT_IEEE);
@@ -169,10 +170,9 @@ arm_cpu_builtins (struct cpp_reader* pfile)
   def_or_undef_macro (pfile, "__ARM_NEON__", TARGET_NEON);
   def_or_undef_macro (pfile, "__ARM_NEON", TARGET_NEON);
 
+  cpp_undef (pfile, "__ARM_NEON_FP");
   if (TARGET_NEON_FP)
     builtin_define_with_int_value ("__ARM_NEON_FP", TARGET_NEON_FP);
-  else
-    cpp_undef (pfile, "__ARM_NEON_FP");
 
   /* Add a define for interworking. Needed when building libgcc.a.  */
   if (arm_cpp_interwork)
diff --git a/gcc/testsuite/gcc.target/arm/pragma_arch_switch_2.c b/gcc/testsuite/gcc.target/arm/pragma_arch_switch_2.c
index fe52191c32c037fe4096c1884e1f6397318bd6a3..7f297557d555fd139a3b804d354117239a78ae62 100644
--- a/gcc/testsuite/gcc.target/arm/pragma_arch_switch_2.c
+++ b/gcc/testsuite/gcc.target/arm/pragma_arch_switch_2.c
@@ -2,16 +2,16 @@
 /* { dg-skip-if "instruction not valid on thumb" { *-*-* } { "-mthumb" } { "" } } */
 /* { dg-do assemble } */
 /* { dg-require-effective-target arm_arm_ok } */
-/* { dg-additional-options "-Wall -O2 -march=armv4t -std=gnu99 -marm" } */
+/* { dg-additional-options "-Wall -O2 -march=armv5t -std=gnu99 -marm" } */
 
-#pragma GCC target ("arch=armv5te")
-void cpu_has_iwmmxt (void)
+#pragma GCC target ("arch=armv6")
+int test_assembly (int hi, int lo)
 {
-   int lo;
-   int hi;
+   int res;
    __asm__ __volatile__ (
-      "mcrr   p0, 0, %2, %3, c0\n"
-      : "=r" (lo), "=r" (hi)
-      : "r" (0), "r" (0x100));
+      "uxtah   %0, %1, %2\n"
+      : "=r" (res)
+      : "r" (hi),  "r" (lo));
+   return res;
 }