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| author | Victor Stinner <victor.stinner@gmail.com> | 2017-04-21 09:24:34 (GMT) |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2017-04-21 09:24:34 (GMT) |
| commit | 28205b203a4742c40080b4a2b4b2dcd800716edc (patch) | |
| tree | cf926f066b2c8b2e3b2f5273475f751ba877ba03 | |
| parent | 791dc831198f3ecc1531f8e6f05debf4ce234d00 (diff) | |
| download | cpython-28205b203a4742c40080b4a2b4b2dcd800716edc.zip cpython-28205b203a4742c40080b4a2b4b2dcd800716edc.tar.gz cpython-28205b203a4742c40080b4a2b4b2dcd800716edc.tar.bz2 | |
bpo-30104: Use -fno-strict-aliasing on clang (#1221)
Python/dtoa.c is not compiled correctly with clang 4.0 and
optimization level -O2 or higher, because of an aliasing issue on
the double/ULong[2] union.
LLVM bug report:
https://bugs.llvm.org//show_bug.cgi?id=31928
| -rwxr-xr-x | configure | 22 | ||||
| -rw-r--r-- | configure.ac | 22 |
2 files changed, 32 insertions, 12 deletions
@@ -6814,8 +6814,15 @@ then # Clang also needs -fwrapv case $CC in - *clang*) WRAP="-fwrapv" - ;; + *clang*) + WRAP="-fwrapv" + # bpo-30104: Python/dtoa.c requires to be build with + # -fno-strict-aliasing to fix compiler issue on the + # double/ULong[2] union using clang 4.0 and optimization level + # -O2 or higher + # https://bugs.llvm.org//show_bug.cgi?id=31928 + ALIASING="-fno-strict-aliasing" + ;; esac case $ac_cv_prog_cc_g in @@ -6824,18 +6831,21 @@ then # Optimization messes up debuggers, so turn it off for # debug builds. if "$CC" -v --help 2>/dev/null |grep -- -Og > /dev/null; then - OPT="-g -Og -Wall $STRICT_PROTO" + OPT="-g -Og -Wall" else - OPT="-g -O0 -Wall $STRICT_PROTO" + OPT="-g -O0 -Wall" fi else - OPT="-g $WRAP -O3 -Wall $STRICT_PROTO" + OPT="-g $WRAP -O3 -Wall" fi ;; *) - OPT="-O3 -Wall $STRICT_PROTO" + OPT="-O3 -Wall" ;; esac + + OPT="$OPT $STRICT_PROTO $ALIASING" + case $ac_sys_system in SCO_SV*) OPT="$OPT -m486 -DSCO5" ;; diff --git a/configure.ac b/configure.ac index d7316b9..cb79ea8 100644 --- a/configure.ac +++ b/configure.ac @@ -1454,8 +1454,15 @@ then # Clang also needs -fwrapv case $CC in - *clang*) WRAP="-fwrapv" - ;; + *clang*) + WRAP="-fwrapv" + # bpo-30104: Python/dtoa.c requires to be build with + # -fno-strict-aliasing to fix compiler issue on the + # double/ULong[2] union using clang 4.0 and optimization level + # -O2 or higher + # https://bugs.llvm.org//show_bug.cgi?id=31928 + ALIASING="-fno-strict-aliasing" + ;; esac case $ac_cv_prog_cc_g in @@ -1464,18 +1471,21 @@ then # Optimization messes up debuggers, so turn it off for # debug builds. if "$CC" -v --help 2>/dev/null |grep -- -Og > /dev/null; then - OPT="-g -Og -Wall $STRICT_PROTO" + OPT="-g -Og -Wall" else - OPT="-g -O0 -Wall $STRICT_PROTO" + OPT="-g -O0 -Wall" fi else - OPT="-g $WRAP -O3 -Wall $STRICT_PROTO" + OPT="-g $WRAP -O3 -Wall" fi ;; *) - OPT="-O3 -Wall $STRICT_PROTO" + OPT="-O3 -Wall" ;; esac + + OPT="$OPT $STRICT_PROTO $ALIASING" + case $ac_sys_system in SCO_SV*) OPT="$OPT -m486 -DSCO5" ;; |