[cfe-dev] Performance alloca + memcpy vs alloca + inline

[Stefan de Konink]

Hi,

While I was looking for vectorisation solutions I stumbled of a strange 
performance difference between clang and gcc.

The attached code can be compile with:

clang -DSINGLE -std=c99 -O3 expanding-inline-generic.c
(poor performance > ~)

vs

clang -DINLINE -std=c99 -O3 expanding-inline-generic.c
(performs fast < 1s)


Using GCC 4.7/4.8 both examples have no noticible differences.

Stefan
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