http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47860
Summary: is vectorization of "condition in nested loop"
supported
Product: gcc
Version: 4.6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: vincenzo.innoce...@cern.ch
In
http://gcc.gnu.org/projects/tree-ssa/vectorization.html#nested
I read that "condition in nested loop" was committed in the main line in
2009-12-03
for 4.6.0 I still get it non vectorize.
what is the real situation of the feature described ion the page above?
for instance
nestedCond.cc:2: note: not vectorized: control flow in loop.
nestedCond.cc:7: note: not vectorized: data ref analysis failed next_a_22 =
*D.2335_21;
full details below
cat nestedCond.cc
void nestedCond( double * __restrict__ x_in, double * __restrict__ x_out,
double * __restrict__ a, double * __restrict__ c, unsigned int M, unsigned int
N) {
for (unsigned int j = 0; j < M; j++)
{
double x = x_in[j];
double curr_a = a[0];
for (unsigned int i = 0; i < N; i++)
{
double next_a = a[i+1];
curr_a = x > c[i] ? curr_a : next_a;
}
x_out[j] = curr_a;
}
}
g++ $CXXFLAGS $OPTFLAGS -v -c nestedCond.cc
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/usr/local/libexec/gcc/x86_64-unknown-linux-gnu/4.6.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ./configure --enable-gold=yes --enable-lto --with-fpmath=avx
Thread model: posix
gcc version 4.6.0 20110205 (experimental) (GCC)
COLLECT_GCC_OPTIONS='-O2' '-std=gnu++0x' '-mavx' '-mtune=corei7-avx'
'-ftree-vectorize' '-ftree-vectorizer-verbose=7' '-pthread' '-fPIC'
'-fassociative-math' '-freciprocal-math' '-fno-math-errno' '-fno-signed-zeros'
'-fno-trapping-math' '-ffinite-math-only' '-v' '-c' '-shared-libgcc'
'-march=x86-64'
/usr/local/libexec/gcc/x86_64-unknown-linux-gnu/4.6.0/cc1plus -quiet -v
-D_GNU_SOURCE -D_REENTRANT nestedCond.cc -quiet -dumpbase nestedCond.cc -mavx
-mtune=corei7-avx -march=x86-64 -auxbase nestedCond -O2 -std=gnu++0x -version
-ftree-vectorize -ftree-vectorizer-verbose=7 -fPIC -fassociative-math
-freciprocal-math -fno-math-errno -fno-signed-zeros -fno-trapping-math
-ffinite-math-only -o /tmp/innocent/ccmT7uly.s
GNU C++ (GCC) version 4.6.0 20110205 (experimental) (x86_64-unknown-linux-gnu)
compiled by GNU C version 4.6.0 20110205 (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
"/usr/local/lib/gcc/x86_64-unknown-linux-gnu/4.6.0/../../../../x86_64-unknown-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/local/lib/gcc/x86_64-unknown-linux-gnu/4.6.0/../../../../include/c++/4.6.0
/usr/local/lib/gcc/x86_64-unknown-linux-gnu/4.6.0/../../../../include/c++/4.6.0/x86_64-unknown-linux-gnu
/usr/local/lib/gcc/x86_64-unknown-linux-gnu/4.6.0/../../../../include/c++/4.6.0/backward
/usr/local/lib/gcc/x86_64-unknown-linux-gnu/4.6.0/include
/usr/local/include
/usr/local/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 20110205 (experimental) (x86_64-unknown-linux-gnu)
compiled by GNU C version 4.6.0 20110205 (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: 0d52c927b640361d99f7371685058a2b
nestedCond.cc:2: note: not vectorized: control flow in loop.
nestedCond.cc:7: note: not vectorized: data ref analysis failed next_a_22 =
*D.2335_21;
nestedCond.cc:1: note: vectorized 0 loops in function.
COLLECT_GCC_OPTIONS='-O2' '-std=gnu++0x' '-mavx' '-mtune=corei7-avx'
'-ftree-vectorize' '-ftree-vectorizer-verbose=7' '-pthread' '-fPIC'
'-fassociative-math' '-freciprocal-math' '-fno-math-errno' '-fno-signed-zeros'
'-fno-trapping-math' '-ffinite-math-only' '-v' '-c' '-shared-libgcc'
'-march=x86-64'
as --64 -msse2avx -o nestedCond.o /tmp/innocent/ccmT7uly.s
COMPILER_PATH=/usr/local/libexec/gcc/x86_64-unknown-linux-gnu/4.6.0/:/usr/local/libexec/gcc/x86_64-unknown-linux-gnu/4.6.0/:/usr/local/libexec/gcc/x86_64-unknown-linux-gnu/:/usr/local/lib/gcc/x86_64-unknown-linux-gnu/4.6.0/:/usr/local/lib/gcc/x86_64-unknown-linux-gnu/
LIBRARY_PATH=/usr/local/lib/gcc/x86_64-unknown-linux-gnu/4.6.0/:/usr/local/lib/gcc/x86_64-unknown-linux-gnu/4.6.0/../../../../lib64/:/lib/../lib64/:/usr/lib/../lib64/:/usr/local/lib/gcc/x86_64-unknown-linux-gnu/4.6.0/../../../:/lib/:/usr/lib/
COLLECT_GCC_OPTIONS='-O2' '-std=gnu++0x' '-mavx' '-mtune=corei7-avx'
'-ftree-vectorize' '-ftree-vectorizer-verbose=7' '-pthread' '-fPIC'
'-fassociative-math' '-freciprocal-math' '-fno-math-errno' '-fno-signed-zeros'
'-fno-trapping-math' '-ffinite-math-only' '-v' '-c' '-shared-libgcc'
'-march=x86-64'
