on
Linux 2.6.18-164.11.1.el5 #1 SMP Wed Jan 20 12:36:24 CET 2010 x86_64 x86_64
x86_64 GNU/Linux
gcc version 4.6.0 20100408 (experimental) (GCC)
and
GNU C++ (GCC) version 4.5.0 (x86_64-unknown-linux-gnu)
#include<cmath>
float sqr(float x) { return std::pow(x,2);}
produces
0000000000000020 <sqr(float)>:
20: 0f 14 c0 unpcklps %xmm0,%xmm0
23: 0f 5a c0 cvtps2pd %xmm0,%xmm0
26: f2 0f 59 c0 mulsd %xmm0,%xmm0
2a: 66 0f 14 c0 unpcklpd %xmm0,%xmm0
2e: 66 0f 5a c0 cvtpd2ps %xmm0,%xmm0
32: c3 retq
33: 66 0f 1f 44 00 00 nopw 0x0(%rax,%rax,1)
39: 0f 1f 80 00 00 00 00 nopl 0x0(%rax)
when compiled with c++ -O2 -std=gnu++0x
while c++ -O2 emits (as expected)
0000000000000020 <sqr(float)>:
20: f3 0f 59 c0 mulss %xmm0,%xmm0
24: c3 retq
25: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1)
2a: 66 0f 1f 44 00 00 nopw 0x0(%rax,%rax,1)
compilation step details
c++ -O2 -std=gnu++0x -c -v assocMath.cpp
Using built-in specs.
COLLECT_GCC=c++
COLLECT_LTO_WRAPPER=/afs/cern.ch/sw/lcg/contrib/gcc/4.5.0_20100409/x86_64-slc5-gcc43-opt/libexec/gcc/x86_64-unknown-linux-gnu/4.6.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: /build/LCG/work/gcc-4.5.0_20100409/configure
--prefix=/afs/cern.ch/sw/lcg/contrib/gcc/4.5.0_20100409/x86_64-slc5-gcc43-opt
--with-mpfr=/afs/cern.ch/sw/lcg/external/mpfr/2.4.2/x86_64-slc5-gcc43-opt
--with-gmp=/afs/cern.ch/sw/lcg/external/gmp/4.3.2/x86_64-slc5-gcc43-opt
--with-mpc=/afs/cern.ch/sw/lcg/external/mpc/0.8.1/x86_64-slc5-gcc43-opt
--enable-lto
--with-libelf=/afs/cern.ch/sw/lcg/external/libelf/0.8.13/x86_64-slc5-gcc43-opt
--with-ppl=/afs/cern.ch/sw/lcg/external/ppl/0.10.2/x86_64-slc5-gcc43-opt
--with-cloog=/afs/cern.ch/sw/lcg/external/cloog-ppl/0.15.7/x86_64-slc5-gcc43-opt
--enable-languages=c,c++,fortran --disable-werror
Thread model: posix
gcc version 4.6.0 20100408 (experimental) (GCC)
COLLECT_GCC_OPTIONS='-O2' '-std=gnu++0x' '-c' '-v' '-shared-libgcc'
'-mtune=generic' '-march=x86-64'
/afs/cern.ch/sw/lcg/contrib/gcc/4.5.0_20100409/x86_64-slc5-gcc43-opt/libexec/gcc/x86_64-unknown-linux-gnu/4.6.0/cc1plus
-quiet -v -D_GNU_SOURCE assocMath.cpp -quiet -dumpbase assocMath.cpp
-mtune=generic -march=x86-64 -auxbase assocMath -O2 -std=gnu++0x -version -o
/tmp/innocent/ccQs7YW8.s
GNU C++ (GCC) version 4.6.0 20100408 (experimental) (x86_64-unknown-linux-gnu)
compiled by GNU C version 4.6.0 20100408 (experimental), GMP version
4.3.2, MPFR version 2.4.2, MPC version 0.8.1
GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096
ignoring nonexistent directory
"/afs/cern.ch/sw/lcg/contrib/gcc/4.5.0_20100409/x86_64-slc5-gcc43-opt/lib/gcc/x86_64-unknown-linux-gnu/4.6.0/../../../../x86_64-unknown-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
/afs/cern.ch/sw/lcg/contrib/gcc/4.5.0_20100409/x86_64-slc5-gcc43-opt/lib/gcc/x86_64-unknown-linux-gnu/4.6.0/../../../../include/c++/4.6.0
/afs/cern.ch/sw/lcg/contrib/gcc/4.5.0_20100409/x86_64-slc5-gcc43-opt/lib/gcc/x86_64-unknown-linux-gnu/4.6.0/../../../../include/c++/4.6.0/x86_64-unknown-linux-gnu
/afs/cern.ch/sw/lcg/contrib/gcc/4.5.0_20100409/x86_64-slc5-gcc43-opt/lib/gcc/x86_64-unknown-linux-gnu/4.6.0/../../../../include/c++/4.6.0/backward
/usr/local/include
/afs/cern.ch/sw/lcg/contrib/gcc/4.5.0_20100409/x86_64-slc5-gcc43-opt/include
/afs/cern.ch/sw/lcg/contrib/gcc/4.5.0_20100409/x86_64-slc5-gcc43-opt/lib/gcc/x86_64-unknown-linux-gnu/4.6.0/include
/afs/cern.ch/sw/lcg/contrib/gcc/4.5.0_20100409/x86_64-slc5-gcc43-opt/lib/gcc/x86_64-unknown-linux-gnu/4.6.0/include-fixed
/usr/include
End of search list.
GNU C++ (GCC) version 4.6.0 20100408 (experimental) (x86_64-unknown-linux-gnu)
compiled by GNU C version 4.6.0 20100408 (experimental), GMP version
4.3.2, MPFR version 2.4.2, MPC version 0.8.1
GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096
Compiler executable checksum: c599e68b8adba71320a274af3bca4ed6
COLLECT_GCC_OPTIONS='-O2' '-std=gnu++0x' '-c' '-v' '-shared-libgcc'
'-mtune=generic' '-march=x86-64'
as -V -Qy --64 -o assocMath.o /tmp/innocent/ccQs7YW8.s
GNU assembler version 2.17.50.0.6-12.el5 (x86_64-redhat-linux) using BFD
version 2.17.50.0.6-12.el5 20061020
COMPILER_PATH=/afs/cern.ch/sw/lcg/contrib/gcc/4.5.0_20100409/x86_64-slc5-gcc43-opt/libexec/gcc/x86_64-unknown-linux-gnu/4.6.0/:/afs/cern.ch/sw/lcg/contrib/gcc/4.5.0_20100409/x86_64-slc5-gcc43-opt/libexec/gcc/x86_64-unknown-linux-gnu/4.6.0/:/afs/cern.ch/sw/lcg/contrib/gcc/4.5.0_20100409/x86_64-slc5-gcc43-opt/libexec/gcc/x86_64-unknown-linux-gnu/:/afs/cern.ch/sw/lcg/contrib/gcc/4.5.0_20100409/x86_64-slc5-gcc43-opt/lib/gcc/x86_64-unknown-linux-gnu/4.6.0/:/afs/cern.ch/sw/lcg/contrib/gcc/4.5.0_20100409/x86_64-slc5-gcc43-opt/lib/gcc/x86_64-unknown-linux-gnu/
LIBRARY_PATH=/afs/cern.ch/sw/lcg/contrib/gcc/4.5.0_20100409/x86_64-slc5-gcc43-opt/lib/gcc/x86_64-unknown-linux-gnu/4.6.0/:/afs/cern.ch/sw/lcg/contrib/gcc/4.5.0_20100409/x86_64-slc5-gcc43-opt/lib/gcc/x86_64-unknown-linux-gnu/4.6.0/../../../../lib64/:/lib/../lib64/:/usr/lib/../lib64/:/afs/cern.ch/sw/lcg/contrib/gcc/4.5.0_20100409/x86_64-slc5-gcc43-opt/lib/gcc/x86_64-unknown-linux-gnu/4.6.0/../../../:/lib/:/usr/lib/
COLLECT_GCC_OPTIONS='-O2' '-std=gnu++0x' '-c' '-v' '-shared-libgcc'
'-mtune=generic' '-march=x86-64'
same with
GNU C++ (GCC) version 4.5.0 (x86_64-unknown-linux-gnu)
compiled by GNU C version 4.5.0, GMP version 4.3.2, MPFR version 2.4.2,
MPC version 0.8.1
if fixed please backport to 4.5.x
--
Summary: std::pow(float) converts to double when compiled with -
std=gnu++0x
Product: gcc
Version: 4.6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: vincenzo dot innocente at cern dot ch
GCC target triplet: x86_64-unknown-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45542
