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| author | Xi Ruoyao <xry111@xry111.site> | 2023-11-24 11:08:19 +0800 |
|---|---|---|
| committer | Xi Ruoyao <xry111@xry111.site> | 2023-12-12 19:21:57 +0800 |
| commit | 99182ea09f10beca8445396cbab491899536f5c3 (patch) | |
| tree | d46fecc89e464b5287886d9c79fab280f0134d03 | |
| parent | 0640bc76cd0937069bdeea71aa9e1076d633ed97 (diff) | |
| download | gcc-99182ea09f10beca8445396cbab491899536f5c3.zip gcc-99182ea09f10beca8445396cbab491899536f5c3.tar.gz gcc-99182ea09f10beca8445396cbab491899536f5c3.tar.bz2 | |
Only allow (int)trunc(x) to (int)x simplification with -ffp-int-builtin-inexact [PR107723]
With -fno-fp-int-builtin-inexact, trunc is not allowed to raise
FE_INEXACT and it should produce an integral result (if the input is not
NaN or Inf). Thus FE_INEXACT should not be raised.
But (int)x may raise FE_INEXACT when x is a non-integer, non-NaN, and
non-Inf value. C23 recommends to do so in a footnote.
Thus we should not simplify (int)trunc(x) to (int)x if
-fno-fp-int-builtin-inexact is in-effect.
gcc/ChangeLog:
PR middle-end/107723
* convert.cc (convert_to_integer_1) [case BUILT_IN_TRUNC]: Break
early if !flag_fp_int_builtin_inexact and flag_trapping_math.
gcc/testsuite/ChangeLog:
PR middle-end/107723
* gcc.dg/torture/builtin-fp-int-inexact-trunc.c: New test.
| -rw-r--r-- | gcc/convert.cc | 3 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.dg/torture/builtin-fp-int-inexact-trunc.c | 12 |
2 files changed, 14 insertions, 1 deletions
diff --git a/gcc/convert.cc b/gcc/convert.cc index 46c8bcb..f214b75 100644 --- a/gcc/convert.cc +++ b/gcc/convert.cc @@ -591,7 +591,8 @@ convert_to_integer_1 (tree type, tree expr, bool dofold) CASE_FLT_FN (BUILT_IN_TRUNC): CASE_FLT_FN_FLOATN_NX (BUILT_IN_TRUNC): if (call_expr_nargs (s_expr) != 1 - || !SCALAR_FLOAT_TYPE_P (TREE_TYPE (CALL_EXPR_ARG (s_expr, 0)))) + || !SCALAR_FLOAT_TYPE_P (TREE_TYPE (CALL_EXPR_ARG (s_expr, 0))) + || (!flag_fp_int_builtin_inexact && flag_trapping_math)) break; return convert_to_integer_1 (type, CALL_EXPR_ARG (s_expr, 0), dofold); diff --git a/gcc/testsuite/gcc.dg/torture/builtin-fp-int-inexact-trunc.c b/gcc/testsuite/gcc.dg/torture/builtin-fp-int-inexact-trunc.c new file mode 100644 index 0000000..0973118 --- /dev/null +++ b/gcc/testsuite/gcc.dg/torture/builtin-fp-int-inexact-trunc.c @@ -0,0 +1,12 @@ +/* Test -fno-fp-int-builtin-inexact. */ +/* { dg-do compile } */ +/* { dg-options "-fno-fp-int-builtin-inexact -fdump-tree-original" } */ + +long +x (double y) +{ + return __builtin_trunc (y); +} + +/* Optimization should not discard the __builtin_trunc call. */ +/* { dg-final { scan-tree-dump "__builtin_trunc" "original" } } */ |