Hi, this patches fixes profile updating in the ifcombine. This is not hard to do and ifcombine is #2 profile update offender out of tree passes (#1 is the vectorizer).
I think this counts as a regression, becuase one can trigger arbitrarily bad profile after ifconversion and defnitly construct a testcase where this will cause us optimize for size where we optimized for speed previously. Bootstrapped/regtested x86_64-linux. Will commit it tomorrow (after testers pick up the threading fix) unless there are complains. * gcc.dg/tree-ssa/ssa-ifcombine-1.c: Check for no profile mismatches. * gcc.dg/tree-ssa/ssa-ifcombine-2.c: Check for no profile mismatches. * gcc.dg/tree-ssa/ssa-ifcombine-3.c: Check for no profile mismatches. * gcc.dg/tree-ssa/ssa-ifcombine-4.c: Check for no profile mismatches. * gcc.dg/tree-ssa/ssa-ifcombine-5.c: Check for no profile mismatches. * gcc.dg/tree-ssa/ssa-ifcombine-6.c: Check for no profile mismatches. * gcc.dg/tree-ssa/ssa-ifcombine-7.c: Check for no profile mismatches. * gcc.dg/tree-ssa/ssa-ifcombine-8.c: Check for no profile mismatches. * gcc.dg/tree-ssa/ssa-ifcombine-9.c: Check for no profile mismatches. * gcc.dg/tree-ssa/ssa-ifcombine-10.c: Check for no profile mismatches. * gcc.dg/tree-ssa/ssa-ifcombine-11.c: Check for no profile mismatches. * gcc.dg/tree-ssa/ssa-ifcombine-12.c: Check for no profile mismatches. * gcc.dg/tree-ssa/ssa-ifcombine-13.c: Check for no profile mismatches. * tree-ssa-ifcombine.c (update_profile_after_ifcombine): New function. (ifcombine_ifandif): Use it. Index: testsuite/gcc.dg/tree-ssa/ssa-ifcombine-1.c =================================================================== --- testsuite/gcc.dg/tree-ssa/ssa-ifcombine-1.c (revision 245134) +++ testsuite/gcc.dg/tree-ssa/ssa-ifcombine-1.c (working copy) @@ -1,5 +1,5 @@ /* { dg-do compile } */ -/* { dg-options "-O -fdump-tree-optimized" } */ +/* { dg-options "-O -fdump-tree-optimized-details-blocks" } */ /* Testcase for PR31657. */ @@ -14,3 +14,4 @@ int foo (int x, int a, int b) } /* { dg-final { scan-tree-dump "\\|" "optimized" } } */ +/* { dg-final { scan-tree-dump-not "Invalid sum" "optimized" } } */ Index: testsuite/gcc.dg/tree-ssa/ssa-ifcombine-10.c =================================================================== --- testsuite/gcc.dg/tree-ssa/ssa-ifcombine-10.c (revision 245134) +++ testsuite/gcc.dg/tree-ssa/ssa-ifcombine-10.c (working copy) @@ -1,5 +1,5 @@ /* { dg-do compile } */ -/* { dg-options "-O2 -fdump-tree-optimized" } */ +/* { dg-options "-O2 -fdump-tree-optimized-details-blocks" } */ /* Testcase for PR31657. */ @@ -17,3 +17,4 @@ int f(int x, int a, int b) return t; } /* { dg-final { scan-tree-dump "& 5" "optimized" } } */ +/* { dg-final { scan-tree-dump-not "Invalid sum" "optimized" } } */ Index: testsuite/gcc.dg/tree-ssa/ssa-ifcombine-11.c =================================================================== --- testsuite/gcc.dg/tree-ssa/ssa-ifcombine-11.c (revision 245134) +++ testsuite/gcc.dg/tree-ssa/ssa-ifcombine-11.c (working copy) @@ -1,5 +1,5 @@ /* { dg-do compile } */ -/* { dg-options "-O -fdump-tree-optimized" } */ +/* { dg-options "-O -fdump-tree-optimized-details-blocks" } */ /* Testcase for PR31657. */ int g(void); @@ -18,3 +18,4 @@ int f(int x, int a, int b) } /* { dg-final { scan-tree-dump "& 5" "optimized" } } */ +/* { dg-final { scan-tree-dump-not "Invalid sum" "optimized" } } */ Index: testsuite/gcc.dg/tree-ssa/ssa-ifcombine-12.c =================================================================== --- testsuite/gcc.dg/tree-ssa/ssa-ifcombine-12.c (revision 245134) +++ testsuite/gcc.dg/tree-ssa/ssa-ifcombine-12.c (working copy) @@ -1,5 +1,5 @@ /* { dg-do compile } */ -/* { dg-options "-O2 -fno-tree-vrp -fdump-tree-optimized" } */ +/* { dg-options "-O2 -fno-tree-vrp -fdump-tree-optimized-details-blocks" } */ /* Testcase for PR31657. */ @@ -17,3 +17,4 @@ int f(int x, int a, int b) return t; } /* { dg-final { scan-tree-dump "& 5" "optimized" } } */ +/* { dg-final { scan-tree-dump-not "Invalid sum" "optimized" } } */ Index: testsuite/gcc.dg/tree-ssa/ssa-ifcombine-13.c =================================================================== --- testsuite/gcc.dg/tree-ssa/ssa-ifcombine-13.c (revision 245134) +++ testsuite/gcc.dg/tree-ssa/ssa-ifcombine-13.c (working copy) @@ -1,5 +1,5 @@ /* { dg-do compile } */ -/* { dg-options "-O1 -fdump-tree-optimized" } */ +/* { dg-options "-O1 -fdump-tree-optimized-details-blocks" } */ /* { dg-additional-options "-mbranch-cost=2" { target { i?86-*-* x86_64-*-* s390*-*-* avr*-*-* } } } */ _Bool f1(_Bool a, _Bool b) @@ -18,3 +18,4 @@ _Bool f1(_Bool a, _Bool b) /* 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-*-* s390*-*-* avr*-*-* } } } } */ +/* { dg-final { scan-tree-dump-not "Invalid sum" "optimized" } } */ Index: testsuite/gcc.dg/tree-ssa/ssa-ifcombine-2.c =================================================================== --- testsuite/gcc.dg/tree-ssa/ssa-ifcombine-2.c (revision 245134) +++ testsuite/gcc.dg/tree-ssa/ssa-ifcombine-2.c (working copy) @@ -1,5 +1,5 @@ /* { dg-do compile } */ -/* { dg-options "-O -fdump-tree-optimized" } */ +/* { dg-options "-O -fdump-tree-optimized-details-blocks" } */ /* Testcase for PR31657. */ @@ -20,3 +20,4 @@ doit: } /* { dg-final { scan-tree-dump "\\|" "optimized" } } */ +/* { dg-final { scan-tree-dump-not "Invalid sum" "optimized" } } */ Index: testsuite/gcc.dg/tree-ssa/ssa-ifcombine-3.c =================================================================== --- testsuite/gcc.dg/tree-ssa/ssa-ifcombine-3.c (revision 245134) +++ testsuite/gcc.dg/tree-ssa/ssa-ifcombine-3.c (working copy) @@ -1,5 +1,5 @@ /* { dg-do compile } */ -/* { dg-options "-O -fdump-tree-optimized" } */ +/* { dg-options "-O -fdump-tree-optimized-details-blocks" } */ /* Testcase extracted from PR15353. */ @@ -20,3 +20,4 @@ doit: } /* { dg-final { scan-tree-dump ">=" "optimized" } } */ +/* { dg-final { scan-tree-dump-not "Invalid sum" "optimized" } } */ Index: testsuite/gcc.dg/tree-ssa/ssa-ifcombine-4.c =================================================================== --- testsuite/gcc.dg/tree-ssa/ssa-ifcombine-4.c (revision 245134) +++ testsuite/gcc.dg/tree-ssa/ssa-ifcombine-4.c (working copy) @@ -1,5 +1,5 @@ /* { dg-do compile } */ -/* { dg-options "-O -fdump-tree-optimized" } */ +/* { dg-options "-O -fdump-tree-optimized-details-blocks" } */ /* Testcase extracted from PR15353. */ @@ -18,3 +18,4 @@ void foo (int x, int a) } /* { dg-final { scan-tree-dump "!=" "optimized" } } */ +/* { dg-final { scan-tree-dump-not "Invalid sum" "optimized" } } */ Index: testsuite/gcc.dg/tree-ssa/ssa-ifcombine-5.c =================================================================== --- testsuite/gcc.dg/tree-ssa/ssa-ifcombine-5.c (revision 245134) +++ testsuite/gcc.dg/tree-ssa/ssa-ifcombine-5.c (working copy) @@ -1,5 +1,5 @@ /* { dg-do compile } */ -/* { dg-options "-O -fdump-tree-optimized" } */ +/* { dg-options "-O -fdump-tree-optimized-details-blocks" } */ /* Testcase from PR15353. */ @@ -17,3 +17,4 @@ int f(int *i, int *j) } /* { dg-final { scan-tree-dump ">=" "optimized" } } */ +/* { dg-final { scan-tree-dump-not "Invalid sum" "optimized" } } */ Index: testsuite/gcc.dg/tree-ssa/ssa-ifcombine-6.c =================================================================== --- testsuite/gcc.dg/tree-ssa/ssa-ifcombine-6.c (revision 245134) +++ testsuite/gcc.dg/tree-ssa/ssa-ifcombine-6.c (working copy) @@ -1,5 +1,5 @@ /* { dg-do compile } */ -/* { dg-options "-O -fdump-tree-ifcombine" } */ +/* { dg-options "-O -fdump-tree-ifcombine-details-blocks" } */ void bar (void); @@ -34,3 +34,4 @@ foo2 (unsigned int a) /* { dg-final { scan-tree-dump "optimizing bits or bits test" "ifcombine" } } */ /* { dg-final { scan-tree-dump "optimizing double bit test" "ifcombine" } } */ +/* { dg-final { scan-tree-dump-not "Invalid sum" "ifcombine" } } */ Index: testsuite/gcc.dg/tree-ssa/ssa-ifcombine-7.c =================================================================== --- testsuite/gcc.dg/tree-ssa/ssa-ifcombine-7.c (revision 245134) +++ testsuite/gcc.dg/tree-ssa/ssa-ifcombine-7.c (working copy) @@ -1,5 +1,5 @@ /* { dg-do compile } */ -/* { dg-options "-O -fdump-tree-ifcombine" } */ +/* { dg-options "-O -fdump-tree-ifcombine-details-blocks" } */ int test1 (int i, int j) { @@ -12,3 +12,4 @@ int test1 (int i, int j) /* The above should be optimized to a i > j test by ifcombine. */ /* { dg-final { scan-tree-dump " > " "ifcombine" } } */ +/* { dg-final { scan-tree-dump-not "Invalid sum" "ifcombine" } } */ Index: testsuite/gcc.dg/tree-ssa/ssa-ifcombine-8.c =================================================================== --- testsuite/gcc.dg/tree-ssa/ssa-ifcombine-8.c (revision 245134) +++ testsuite/gcc.dg/tree-ssa/ssa-ifcombine-8.c (working copy) @@ -1,5 +1,5 @@ /* { dg-do compile } */ -/* { dg-options "-O -fno-trapping-math -fdump-tree-ifcombine" } */ +/* { dg-options "-O -fno-trapping-math -fdump-tree-ifcombine-details-blocks" } */ double test1 (double i, double j) { @@ -22,3 +22,4 @@ plouf: Instead we get u<=, which is acceptable with -fno-trapping-math. */ /* { dg-final { scan-tree-dump " u<= " "ifcombine" } } */ +/* { dg-final { scan-tree-dump-not "Invalid sum" "ifcombine" } } */ Index: testsuite/gcc.dg/tree-ssa/ssa-ifcombine-9.c =================================================================== --- testsuite/gcc.dg/tree-ssa/ssa-ifcombine-9.c (revision 245134) +++ testsuite/gcc.dg/tree-ssa/ssa-ifcombine-9.c (working copy) @@ -1,5 +1,5 @@ /* { dg-do compile } */ -/* { dg-options "-O2 -fno-trapping-math -fdump-tree-ifcombine" } */ +/* { dg-options "-O2 -fno-trapping-math -fdump-tree-ifcombine-details-blocks" } */ void f (); enum Sign { NEG=-1, ZERO, POS }; @@ -19,3 +19,4 @@ void g (double x) The transformation would also be legal with -ftrapping-math. */ /* { dg-final { scan-tree-dump "optimizing.* < " "ifcombine" } } */ +/* { dg-final { scan-tree-dump-not "Invalid sum" "ifcombine" } } */ Index: testsuite/gcc.dg/tree-ssa/threadbackward-1.c =================================================================== --- testsuite/gcc.dg/tree-ssa/threadbackward-1.c (revision 0) +++ testsuite/gcc.dg/tree-ssa/threadbackward-1.c (working copy) @@ -0,0 +1,9 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fdump-tree-ethread" } */ +char *c; +int t() +{ + for (int i=0;i<5000;i++) + c[i]=i; +} +/* { dg-final { scan-tree-dump-times "Registering FSM jump thread" 1 "ethread"} } */ Index: tree-ssa-ifcombine.c =================================================================== --- tree-ssa-ifcombine.c (revision 245134) +++ tree-ssa-ifcombine.c (working copy) @@ -332,6 +332,51 @@ recognize_bits_test (gcond *cond, tree * return true; } + +/* Update profile after code in outer_cond_bb was adjuted so + outer_cond_bb has no condition. */ + +static void +update_profile_after_ifcombine (basic_block inner_cond_bb, + basic_block outer_cond_bb) +{ + edge outer_to_inner = find_edge (outer_cond_bb, inner_cond_bb); + edge outer2 = (EDGE_SUCC (outer_cond_bb, 0) == outer_to_inner + ? EDGE_SUCC (outer_cond_bb, 1) + : EDGE_SUCC (outer_cond_bb, 0)); + edge inner_taken = EDGE_SUCC (inner_cond_bb, 0); + edge inner_not_taken = EDGE_SUCC (inner_cond_bb, 1); + + if (inner_taken->dest != outer2->dest) + std::swap (inner_taken, inner_not_taken); + gcc_assert (inner_taken->dest == outer2->dest); + + /* In the following we assume that inner_cond_bb has single predecessor. */ + gcc_assert (single_pred_p (inner_cond_bb)); + + /* Path outer_cond_bb->(outer2) needs to be merged into path + outer_cond_bb->(outer_to_inner)->inner_cond_bb->(inner_taken) + and probability of inner_not_taken updated. */ + + outer_to_inner->count = outer_cond_bb->count; + inner_cond_bb->count = outer_cond_bb->count; + inner_taken->count += outer2->count; + outer2->count = 0; + + inner_taken->probability = outer2->probability + + RDIV (outer_to_inner->probability + * inner_taken->probability, + REG_BR_PROB_BASE); + if (inner_taken->probability > REG_BR_PROB_BASE) + inner_taken->probability = REG_BR_PROB_BASE; + inner_not_taken->probability = REG_BR_PROB_BASE + - inner_taken->probability; + + outer_to_inner->probability = REG_BR_PROB_BASE; + inner_cond_bb->frequency = outer_cond_bb->frequency; + outer2->probability = 0; +} + /* If-convert on a and pattern with a common else block. The inner if is specified by its INNER_COND_BB, the outer by OUTER_COND_BB. inner_inv, outer_inv and result_inv indicate whether the conditions @@ -394,6 +439,7 @@ ifcombine_ifandif (basic_block inner_con outer_inv ? boolean_false_node : boolean_true_node); update_stmt (outer_cond); + update_profile_after_ifcombine (inner_cond_bb, outer_cond_bb); if (dump_file) { fprintf (dump_file, "optimizing double bit test to "); @@ -471,6 +518,7 @@ ifcombine_ifandif (basic_block inner_con gimple_cond_set_condition_from_tree (outer_cond, outer_inv ? boolean_false_node : boolean_true_node); update_stmt (outer_cond); + update_profile_after_ifcombine (inner_cond_bb, outer_cond_bb); if (dump_file) { @@ -554,6 +602,7 @@ ifcombine_ifandif (basic_block inner_con gimple_cond_set_condition_from_tree (outer_cond, outer_inv ? boolean_false_node : boolean_true_node); update_stmt (outer_cond); + update_profile_after_ifcombine (inner_cond_bb, outer_cond_bb); if (dump_file) {