diff options
Diffstat (limited to 'gcc/doc/invoke.texi')
| -rw-r--r-- | gcc/doc/invoke.texi | 36 |
1 files changed, 35 insertions, 1 deletions
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index 9a14170..ac2ee59 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -8220,7 +8220,8 @@ by @option{-O2} and also turns on the following optimization flags: -ftree-partial-pre @gol -ftree-slp-vectorize @gol -funswitch-loops @gol --fvect-cost-model} +-fvect-cost-model @gol +-fversion-loops-for-strides} @item -O0 @opindex O0 @@ -10772,6 +10773,30 @@ of the loop on both branches (modified according to result of the condition). Enabled by @option{-fprofile-use} and @option{-fauto-profile}. +@item -fversion-loops-for-strides +@opindex fversion-loops-for-strides +If a loop iterates over an array with a variable stride, create another +version of the loop that assumes the stride is always one. For example: + +@smallexample +for (int i = 0; i < n; ++i) + x[i * stride] = @dots{}; +@end smallexample + +becomes: + +@smallexample +if (stride == 1) + for (int i = 0; i < n; ++i) + x[i] = @dots{}; +else + for (int i = 0; i < n; ++i) + x[i * stride] = @dots{}; +@end smallexample + +This is particularly useful for assumed-shape arrays in Fortran where +(for example) it allows better vectorization assuming contiguous accesses. + @item -ffunction-sections @itemx -fdata-sections @opindex ffunction-sections @@ -11981,6 +12006,15 @@ Hardware autoprefetcher scheduler model control flag. Number of lookahead cycles the model looks into; at ' ' only enable instruction sorting heuristic. +@item loop-versioning-max-inner-insns +The maximum number of instructions that an inner loop can have +before the loop versioning pass considers it too big to copy. + +@item loop-versioning-max-outer-insns +The maximum number of instructions that an outer loop can have +before the loop versioning pass considers it too big to copy, +discounting any instructions in inner loops that directly benefit +from versioning. @end table @end table |