From: Jakub Jelinek Date: Wed, 12 Mar 2014 12:59:03 +0000 (+0100) Subject: tree-ssa-ifcombine.c (forwarder_block_to): New function. X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=bf4787b26777cad2bf7ed499248a350387366d9f;p=gcc.git tree-ssa-ifcombine.c (forwarder_block_to): New function. * tree-ssa-ifcombine.c (forwarder_block_to): New function. (tree_ssa_ifcombine_bb_1): New function. (tree_ssa_ifcombine_bb): Use it. Handle also cases where else_bb is an empty forwarder block to then_bb or vice versa and then_bb and else_bb are effectively swapped. * gcc.dg/tree-ssa/ssa-ifcombine-12.c: New test. * gcc.dg/tree-ssa/ssa-ifcombine-13.c: New test. * gcc.dg/tree-ssa/phi-opt-2.c: Pass -mbranch-cost=1 if possible, only test for exactly one if if -mbranch-cost=1 has been passed. From-SVN: r208512 --- diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 05127c811cf..3863dc1b7c5 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,11 @@ +2014-03-12 Jakub Jelinek + + * tree-ssa-ifcombine.c (forwarder_block_to): New function. + (tree_ssa_ifcombine_bb_1): New function. + (tree_ssa_ifcombine_bb): Use it. Handle also cases where else_bb + is an empty forwarder block to then_bb or vice versa and then_bb + and else_bb are effectively swapped. + 2014-03-12 Christian Bruel PR target/60264 diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 154ebc6254d..5f1297e27b3 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,11 @@ +2014-03-12 Jakub Jelinek + + * gcc.dg/tree-ssa/ssa-ifcombine-12.c: New test. + * gcc.dg/tree-ssa/ssa-ifcombine-13.c: New test. + * gcc.dg/tree-ssa/phi-opt-2.c: Pass -mbranch-cost=1 if + possible, only test for exactly one if if -mbranch-cost=1 + has been passed. + 2014-03-12 Christian Bruel PR target/60264 diff --git a/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-2.c b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-2.c index 415c11777b3..3d34ef3f638 100644 --- a/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-2.c +++ b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-2.c @@ -1,5 +1,6 @@ /* { dg-do compile } */ /* { dg-options "-O1 -fdump-tree-optimized" } */ +/* { dg-additional-options "-mbranch-cost=1" { target { i?86-*-* x86_64-*-* mips*-*-* s390*-*-* avr*-*-* } } } */ _Bool f1(_Bool a, _Bool b) { @@ -17,6 +18,8 @@ _Bool f1(_Bool a, _Bool b) /* There should be only one if, the outer one; the inner one should have been changed to straight line code with the value of b (except that we don't fold ! (b != 0) into b - which can be fixed in a different patch). */ -/* { dg-final { scan-tree-dump-times "if" 1 "optimized"} } */ + which can be fixed in a different patch). + Test this only when known to be !LOGICAL_OP_NON_SHORT_CIRCUIT, + otherwise ifcombine may convert this into return a & b;. */ +/* { dg-final { scan-tree-dump-times "if" 1 "optimized" { target { i?86-*-* x86_64-*-* mips*-*-* s390*-*-* avr*-*-* } } } } */ /* { dg-final { cleanup-tree-dump "optimized" } } */ diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-12.c b/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-12.c new file mode 100644 index 00000000000..5893ba7be79 --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-12.c @@ -0,0 +1,20 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fno-tree-vrp -fdump-tree-optimized" } */ + +/* Testcase for PR31657. */ + +int f(int x, int a, int b) +{ + int t = 0; + int c = 1 << a; + if (!(x & 1)) + t = 0; + else + if (x & (1 << 2)) + t = 3; + else + t = 0; + return t; +} +/* { dg-final { scan-tree-dump "& 5" "optimized" } } */ +/* { dg-final { cleanup-tree-dump "optimized" } } */ diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-13.c b/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-13.c new file mode 100644 index 00000000000..19f892eaa85 --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-ifcombine-13.c @@ -0,0 +1,21 @@ +/* { dg-do compile } */ +/* { dg-options "-O1 -fdump-tree-optimized" } */ +/* { dg-additional-options "-mbranch-cost=2" { target { i?86-*-* x86_64-*-* mips*-*-* s390*-*-* avr*-*-* } } } */ + +_Bool f1(_Bool a, _Bool b) +{ + if (a) + { + if (b) + return 1; + else + return 0; + } + return 0; +} + + +/* For LOGICAL_OP_NON_SHORT_CIRCUIT, this should be optimized + into return a & b;, with no ifs. */ +/* { dg-final { scan-tree-dump-not "if" "optimized" { target { i?86-*-* x86_64-*-* mips*-*-* s390*-*-* avr*-*-* } } } } */ +/* { dg-final { cleanup-tree-dump "optimized" } } */ diff --git a/gcc/tree-ssa-ifcombine.c b/gcc/tree-ssa-ifcombine.c index 38d265f61f4..be28fb00417 100644 --- a/gcc/tree-ssa-ifcombine.c +++ b/gcc/tree-ssa-ifcombine.c @@ -135,6 +135,16 @@ bb_no_side_effects_p (basic_block bb) return true; } +/* Return true if BB is an empty forwarder block to TO_BB. */ + +static bool +forwarder_block_to (basic_block bb, basic_block to_bb) +{ + return empty_block_p (bb) + && single_succ_p (bb) + && single_succ (bb) == to_bb; +} + /* Verify if all PHI node arguments in DEST for edges from BB1 or BB2 to DEST are the same. This makes the CFG merge point free from side-effects. Return true in this case, else false. */ @@ -561,6 +571,99 @@ ifcombine_ifandif (basic_block inner_cond_bb, bool inner_inv, return false; } +/* Helper function for tree_ssa_ifcombine_bb. Recognize a CFG pattern and + dispatch to the appropriate if-conversion helper for a particular + set of INNER_COND_BB, OUTER_COND_BB, THEN_BB and ELSE_BB. + PHI_PRED_BB should be one of INNER_COND_BB, THEN_BB or ELSE_BB. */ + +static bool +tree_ssa_ifcombine_bb_1 (basic_block inner_cond_bb, basic_block outer_cond_bb, + basic_block then_bb, basic_block else_bb, + basic_block phi_pred_bb) +{ + /* The && form is characterized by a common else_bb with + the two edges leading to it mergable. The latter is + guaranteed by matching PHI arguments in the else_bb and + the inner cond_bb having no side-effects. */ + if (phi_pred_bb != else_bb + && recognize_if_then_else (outer_cond_bb, &inner_cond_bb, &else_bb) + && same_phi_args_p (outer_cond_bb, phi_pred_bb, else_bb) + && bb_no_side_effects_p (inner_cond_bb)) + { + /* We have + + if (q) goto inner_cond_bb; else goto else_bb; + + if (p) goto ...; else goto else_bb; + ... + + ... + */ + return ifcombine_ifandif (inner_cond_bb, false, outer_cond_bb, false, + false); + } + + /* And a version where the outer condition is negated. */ + if (phi_pred_bb != else_bb + && recognize_if_then_else (outer_cond_bb, &else_bb, &inner_cond_bb) + && same_phi_args_p (outer_cond_bb, phi_pred_bb, else_bb) + && bb_no_side_effects_p (inner_cond_bb)) + { + /* We have + + if (q) goto else_bb; else goto inner_cond_bb; + + if (p) goto ...; else goto else_bb; + ... + + ... + */ + return ifcombine_ifandif (inner_cond_bb, false, outer_cond_bb, true, + false); + } + + /* The || form is characterized by a common then_bb with the + two edges leading to it mergable. The latter is guaranteed + by matching PHI arguments in the then_bb and the inner cond_bb + having no side-effects. */ + if (phi_pred_bb != then_bb + && recognize_if_then_else (outer_cond_bb, &then_bb, &inner_cond_bb) + && same_phi_args_p (outer_cond_bb, phi_pred_bb, then_bb) + && bb_no_side_effects_p (inner_cond_bb)) + { + /* We have + + if (q) goto then_bb; else goto inner_cond_bb; + + if (q) goto then_bb; else goto ...; + + ... + */ + return ifcombine_ifandif (inner_cond_bb, true, outer_cond_bb, true, + true); + } + + /* And a version where the outer condition is negated. */ + if (phi_pred_bb != then_bb + && recognize_if_then_else (outer_cond_bb, &inner_cond_bb, &then_bb) + && same_phi_args_p (outer_cond_bb, phi_pred_bb, then_bb) + && bb_no_side_effects_p (inner_cond_bb)) + { + /* We have + + if (q) goto inner_cond_bb; else goto then_bb; + + if (q) goto then_bb; else goto ...; + + ... + */ + return ifcombine_ifandif (inner_cond_bb, true, outer_cond_bb, false, + true); + } + + return false; +} + /* Recognize a CFG pattern and dispatch to the appropriate if-conversion helper. We start with BB as the innermost worker basic-block. Returns true if a transformation was done. */ @@ -585,80 +688,33 @@ tree_ssa_ifcombine_bb (basic_block inner_cond_bb) { basic_block outer_cond_bb = single_pred (inner_cond_bb); - /* The && form is characterized by a common else_bb with - the two edges leading to it mergable. The latter is - guaranteed by matching PHI arguments in the else_bb and - the inner cond_bb having no side-effects. */ - if (recognize_if_then_else (outer_cond_bb, &inner_cond_bb, &else_bb) - && same_phi_args_p (outer_cond_bb, inner_cond_bb, else_bb) - && bb_no_side_effects_p (inner_cond_bb)) - { - /* We have - - if (q) goto inner_cond_bb; else goto else_bb; - - if (p) goto ...; else goto else_bb; - ... - - ... - */ - return ifcombine_ifandif (inner_cond_bb, false, outer_cond_bb, false, - false); - } + if (tree_ssa_ifcombine_bb_1 (inner_cond_bb, outer_cond_bb, + then_bb, else_bb, inner_cond_bb)) + return true; - /* And a version where the outer condition is negated. */ - if (recognize_if_then_else (outer_cond_bb, &else_bb, &inner_cond_bb) - && same_phi_args_p (outer_cond_bb, inner_cond_bb, else_bb) - && bb_no_side_effects_p (inner_cond_bb)) + if (forwarder_block_to (else_bb, then_bb)) { - /* We have - - if (q) goto else_bb; else goto inner_cond_bb; - - if (p) goto ...; else goto else_bb; - ... - - ... - */ - return ifcombine_ifandif (inner_cond_bb, false, outer_cond_bb, true, - false); + /* Other possibilities for the && form, if else_bb is + empty forwarder block to then_bb. Compared to the above simpler + forms this can be treated as if then_bb and else_bb were swapped, + and the corresponding inner_cond_bb not inverted because of that. + For same_phi_args_p we look at equality of arguments between + edge from outer_cond_bb and the forwarder block. */ + if (tree_ssa_ifcombine_bb_1 (inner_cond_bb, outer_cond_bb, else_bb, + then_bb, else_bb)) + return true; } - - /* The || form is characterized by a common then_bb with the - two edges leading to it mergable. The latter is guaranteed - by matching PHI arguments in the then_bb and the inner cond_bb - having no side-effects. */ - if (recognize_if_then_else (outer_cond_bb, &then_bb, &inner_cond_bb) - && same_phi_args_p (outer_cond_bb, inner_cond_bb, then_bb) - && bb_no_side_effects_p (inner_cond_bb)) - { - /* We have - - if (q) goto then_bb; else goto inner_cond_bb; - - if (q) goto then_bb; else goto ...; - - ... - */ - return ifcombine_ifandif (inner_cond_bb, true, outer_cond_bb, true, - true); - } - - /* And a version where the outer condition is negated. */ - if (recognize_if_then_else (outer_cond_bb, &inner_cond_bb, &then_bb) - && same_phi_args_p (outer_cond_bb, inner_cond_bb, then_bb) - && bb_no_side_effects_p (inner_cond_bb)) + else if (forwarder_block_to (then_bb, else_bb)) { - /* We have - - if (q) goto inner_cond_bb; else goto then_bb; - - if (q) goto then_bb; else goto ...; - - ... - */ - return ifcombine_ifandif (inner_cond_bb, true, outer_cond_bb, false, - true); + /* Other possibilities for the || form, if then_bb is + empty forwarder block to else_bb. Compared to the above simpler + forms this can be treated as if then_bb and else_bb were swapped, + and the corresponding inner_cond_bb not inverted because of that. + For same_phi_args_p we look at equality of arguments between + edge from outer_cond_bb and the forwarder block. */ + if (tree_ssa_ifcombine_bb_1 (inner_cond_bb, outer_cond_bb, else_bb, + then_bb, then_bb)) + return true; } }