On Sun, Jun 10, 2012 at 4:16 PM, Marc Glisse <marc.gli...@inria.fr> wrote: > Hello, > > currently, tree-ssa-ifcombine handles pairs of imbricated "if"s that share > the same then branch, or the same else branch. There is no particular reason > why it couldn't also handle the case where the then branch of one is the > else branch of the other, which is what I do here. > > Any comments?
The general idea looks good, but I think the patch is too invasive. As far as I can see the only callers with a non-zero 'inv' argument come from ifcombine_ifnotorif and ifcombine_ifnotandif (and both with inv == 2). I would rather see a more localized patch that makes use of invert_tree_comparison to perform the inversion on the call arguments of maybe_fold_and/or_comparisons. Is there any reason that would not work? At least + if (inv & 1) + lcompcode2 = COMPCODE_TRUE - lcompcode2; looks as if it were not semantically correct - you cannot simply invert floating-point comparisons (see the restrictions invert_tree_comparison has). Thanks, Richard. > > 2012-06-10 Marc Glisse <marc.gli...@inria.fr> > > gcc/ > PR tree-optimization/51938 > * fold-const.c (combine_comparisons): Extra argument. Handle inverted > conditions. > (fold_truth_andor_1): Update call to combine_comparisons. > * gimple-fold.c (swap12): New function. > (and_comparisons_1): Extra argument. Handle inverted conditions. > (and_var_with_comparison_1): Update call to and_comparisons_1. > (maybe_fold_and_comparisons): Extra argument. Update call to > and_comparisons_1. > (or_comparisons_1): Extra argument. Handle inverted conditions. > (or_var_with_comparison_1): Update call to or_comparisons_1. > (maybe_fold_or_comparisons): Extra argument. Update call to > or_comparisons_1. > * tree-ssa-ifcombine.c (ifcombine_ifnotandif): New function. > (ifcombine_ifnotorif): New function. > (tree_ssa_ifcombine_bb): Call them. > (ifcombine_iforif): Update call to maybe_fold_or_comparisons. > (ifcombine_ifandif): Update call to maybe_fold_and_comparisons. > * tree-ssa-reassoc.c (eliminate_redundant_comparison): Update calls > to > maybe_fold_or_comparisons and maybe_fold_and_comparisons. > * tree-if-conv.c (fold_or_predicates): Update call to > maybe_fold_or_comparisons. > * gimple.h (maybe_fold_and_comparisons): Match gimple-fold.c > prototype. > (maybe_fold_or_comparisons): Likewise. > * tree.h (combine_comparisons): Match fold-const.c prototype. > > gcc/testsuite/ > PR tree-optimization/51938 > * gcc.dg/tree-ssa/ssa-ifcombine-8.c: New testcase. > * gcc.dg/tree-ssa/ssa-ifcombine-9.c: New testcase. > > > > -- > Marc Glisse
