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| author | liuhongt <hongtao.liu@intel.com> | 2023-06-26 11:46:49 +0800 |
|---|---|---|
| committer | liuhongt <hongtao.liu@intel.com> | 2023-06-28 09:25:35 +0800 |
| commit | 4ae5ad78c32bd775c6da5fd419183d29d6bef38a (patch) | |
| tree | 6a8e23f78f7816834204b4edd457ee127752b2ad /gcc | |
| parent | 878a9fee50b05c63200bd9a9d1e5189b304692ae (diff) | |
| download | gcc-4ae5ad78c32bd775c6da5fd419183d29d6bef38a.zip gcc-4ae5ad78c32bd775c6da5fd419183d29d6bef38a.tar.gz gcc-4ae5ad78c32bd775c6da5fd419183d29d6bef38a.tar.bz2 | |
Issue a warning for conversion between short and __bf16 under TARGET_AVX512BF16.
__bfloat16 is redefined from typedef short to real __bf16 since GCC
V13. The patch issues an warning for potential silent implicit
conversion between __bf16 and short where users may only expect a
data movement.
To avoid too many false positive, warning is only under
TARGET_AVX512BF16.
gcc/ChangeLog:
* config/i386/i386.cc (ix86_invalid_conversion): New function.
(TARGET_INVALID_CONVERSION): Define as
ix86_invalid_conversion.
gcc/testsuite/ChangeLog:
* gcc.target/i386/bf16_short_warn.c: New test.
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/config/i386/i386.cc | 32 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.target/i386/bf16_short_warn.c | 17 |
2 files changed, 49 insertions, 0 deletions
diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc index caca74d..8989985 100644 --- a/gcc/config/i386/i386.cc +++ b/gcc/config/i386/i386.cc @@ -22719,6 +22719,35 @@ x86_emit_floatuns (rtx operands[2]) emit_label (donelab); } + +/* Return the diagnostic message string if conversion from FROMTYPE to + TOTYPE is not allowed, NULL otherwise. + Currently it's used to warn for silent implicit conversion between __bf16 + and short, since __bfloat16 is refined as real __bf16 instead of short + since GCC13. */ + +static const char * +ix86_invalid_conversion (const_tree fromtype, const_tree totype) +{ + if (element_mode (fromtype) != element_mode (totype) + && (TARGET_AVX512BF16 || TARGET_AVXNECONVERT)) + { + /* Warn for silent implicit conversion where user may expect + a bitcast. */ + if ((TYPE_MODE (fromtype) == BFmode + && TYPE_MODE (totype) == HImode) + || (TYPE_MODE (totype) == BFmode + && TYPE_MODE (fromtype) == HImode)) + warning (0, "%<__bfloat16%> is redefined from typedef %<short%> " + "to real %<__bf16%> since GCC V13, be careful of " + "implicit conversion between %<__bf16%> and %<short%>; " + "a explicit bitcast may be needed here"); + } + + /* Conversion allowed. */ + return NULL; +} + /* Target hook for scalar_mode_supported_p. */ static bool @@ -25010,6 +25039,9 @@ ix86_run_selftests (void) # define TARGET_MERGE_DECL_ATTRIBUTES merge_dllimport_decl_attributes #endif +#undef TARGET_INVALID_CONVERSION +#define TARGET_INVALID_CONVERSION ix86_invalid_conversion + #undef TARGET_COMP_TYPE_ATTRIBUTES #define TARGET_COMP_TYPE_ATTRIBUTES ix86_comp_type_attributes diff --git a/gcc/testsuite/gcc.target/i386/bf16_short_warn.c b/gcc/testsuite/gcc.target/i386/bf16_short_warn.c new file mode 100644 index 0000000..3e47a81 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/bf16_short_warn.c @@ -0,0 +1,17 @@ +/* { dg-do compile } */ +/* { dg-options "-O2" } */ + +#include<immintrin.h> +typedef struct { +short payload; +} BFloat16; + +__attribute__((target("avx512vl,avx512bf16"))) +BFloat16 tobf16_avx512(float f) +{ + BFloat16 r; + __m128bh m = _mm_cvtneps_pbh(_mm_set_ss(f)); + r.payload = m[0]; /* { dg-warning " be careful of implicit conversion between '__bf16' and 'short'" } */ + return r; +} + |