[Bug target/32086] [4.3 Regression] 10% to 20% Performance Regression Between 4.1.3 and 4.3

[ubizjak at gmail dot com]

------- Comment #5 from ubizjak at gmail dot com  2007-11-30 10:27 -------
gfortran -march=opteron -ffast-math -funroll-loops -ftree-loop-linear -msse3
-O3 -mfpmath=sse induct.f90:
user    1m32.226s
gfortran -march=opteron -ffast-math -funroll-loops -ftree-loop-linear -msse3
-O3 -mfpmath=sse -fno-tree-vectorize induct.f90
user    0m58.492s
fortran -march=opteron -ffast-math -funroll-loops -ftree-loop-linear -msse3 -O3
-mfpmath=387 induct.f90
user    1m40.906s
gfortran -march=opteron -ffast-math -funroll-loops -ftree-loop-linear -msse3
-O3 -mfpmath=387 -fno-tree-vectorize induct.f90
user    0m46.439s
gfortran -march=opteron -ffast-math -funroll-loops -ftree-loop-linear -msse3
-O3 -mfpmath=sse -fvect-cost-model induct.f90
user    0m58.168s
gfortran -march=opteron -ffast-math -funroll-loops -ftree-loop-linear -msse3
-O3 -mfpmath=387 -fvect-cost-model induct.f90
user    0m46.415s

All on:

Family: 15 Model: 4 Stepping: 10 Type: 0 Brand: 0
CPU Model: Pentium 4 D (Foster) Original OEM
Processor name string: Intel(R) Xeon(TM) CPU 3.60GHz

(so -march=opteron is a bit misleading)

I'd say that vectorizer cost model is doing its job pretty well.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32086