[Bug target/69180] New: [ARM] #pragma GCC target should not warn about redefined macros

[chrbr at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69180

            Bug ID: 69180
           Summary: [ARM] #pragma GCC target should not warn about
                    redefined macros
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: chrbr at gcc dot gnu.org
  Target Milestone: ---

the line :
#pragma GCC target ("fpu=neon")

compiled with  -mfloat-abi=softfp -mfpu=neon-fp-armv8

warns with
warning: "__ARM_NEON_FP" redefined
<built-in>: note: this is the location of the previous definition

breaking a few tests for compiler configured with neon-fp-armv8 as default

This warning should not be necessary as implicitly set, but should only occur
for explicit __ARM_NEON_FP user redefinition (e.g -D__ARM_NEON_FP=0)

the other macro having context sensitive values are __ARM_FP and
__ARM_FEATURE_LDREX