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[3/8] math: Fix UB on logf

Message ID 20250425205618.360232-4-adhemerval.zanella@linaro.org
State New
Headers show
Series Fix UB in math implementations | expand

Commit Message

Adhemerval Zanella April 25, 2025, 8:54 p.m. UTC 
The left shift overflows for 'int', use a literal instead.  It syncs
with OPTIMIZED-ROUTINES commit 0f87f607b976820ef41fe64d004fe67dc7af8236.

Checked on aarch64-linux-gnu, x86_64-linux-gnu, and i686-linux-gnu.
---
 sysdeps/ieee754/flt-32/e_logf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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Patch

diff --git a/sysdeps/ieee754/flt-32/e_logf.c b/sysdeps/ieee754/flt-32/e_logf.c
index 6a595cf7f0..207151c76a 100644
--- a/sysdeps/ieee754/flt-32/e_logf.c
+++ b/sysdeps/ieee754/flt-32/e_logf.c
@@ -70,7 +70,7 @@  __logf (float x)
   tmp = ix - OFF;
   i = (tmp >> (23 - LOGF_TABLE_BITS)) % N;
   k = (int32_t) tmp >> 23; /* arithmetic shift */
-  iz = ix - (tmp & 0x1ff << 23);
+  iz = ix - (tmp & 0xff800000);
   invc = T[i].invc;
   logc = T[i].logc;
   z = (double_t) asfloat (iz);