https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118184
Bug ID: 118184
Summary: [15 regression] glibc regression on aarch64
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: adhemerval.zanella at linaro dot org
Target Milestone: ---
Created attachment 59957
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=59957&action=edit
preprocessed file of the affected routine
The commit
https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff;h=5ab3f091b3eb42795340d3c9cea8aaec2060693c
triggered two glibc regression on aarch64:
FAIL: math/test-nan-payload
FAIL: stdlib/tst-strtod6
On glibc stdlib/strtod_nan_main.c where glibc handles the NaN input for
strtold:
48 /* This is a system-dependent way to specify the bitmask used for
49 the NaN. We expect it to be a number which is put in the
50 mantissa of the number. */
51 STRING_TYPE *endp;
52 unsigned long long int mant;
53
54 int save_errno = errno;
55 mant = STRTOULL (str, &endp, 0);
56 __set_errno (save_errno);
57 if (endp == cp)
58 SET_NAN_PAYLOAD (retval, mant);
59
60 out:
61 if (endptr != NULL)
62 *endptr = (STRING_TYPE *) cp;
63 return retval;
64 }
When building with default -O2 the comparison at line 57 is not true, which
does not net the number to NaN. Building with -O0 does not trigger this issue.
