From: Jakub Jelinek Date: Mon, 22 Jan 2018 22:59:33 +0000 (+0100) Subject: re PR tree-optimization/83081 ([arm] gcc.dg/pr80218.c fails since r254888) X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=f5c517f03c53189f5a3381cda85219303480e090;p=gcc.git re PR tree-optimization/83081 ([arm] gcc.dg/pr80218.c fails since r254888) PR tree-optimization/83081 * profile-count.h (profile_probability::split): New method. * dojump.c (do_jump_1) : Use profile_probability::split. (do_compare_rtx_and_jump): Fix adjustment of probabilities when splitting a single conditional jump into 2. * gcc.dg/predict-8.c: Adjust expected probability. From-SVN: r256966 --- diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 2570832d8b4..d8c30e71916 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,12 @@ +2018-01-22 Jakub Jelinek + + PR tree-optimization/83081 + * profile-count.h (profile_probability::split): New method. + * dojump.c (do_jump_1) : + Use profile_probability::split. + (do_compare_rtx_and_jump): Fix adjustment of probabilities + when splitting a single conditional jump into 2. + 2018-01-22 David Malcolm PR tree-optimization/69452 diff --git a/gcc/dojump.c b/gcc/dojump.c index f86f83eedc1..9da8a0e3091 100644 --- a/gcc/dojump.c +++ b/gcc/dojump.c @@ -347,13 +347,11 @@ do_jump_1 (enum tree_code code, tree op0, tree op1, profile_probability op1_prob = profile_probability::uninitialized (); if (prob.initialized_p ()) { - profile_probability false_prob = prob.invert (); - profile_probability op0_false_prob = false_prob.apply_scale (1, 2); - profile_probability op1_false_prob = false_prob.apply_scale (1, 2) - / op0_false_prob.invert (); + op1_prob = prob.invert (); + op0_prob = op1_prob.split (profile_probability::even ()); /* Get the probability that each jump below is true. */ - op0_prob = op0_false_prob.invert (); - op1_prob = op1_false_prob.invert (); + op0_prob = op0_prob.invert (); + op1_prob = op1_prob.invert (); } if (if_false_label == NULL) { @@ -380,8 +378,8 @@ do_jump_1 (enum tree_code code, tree op0, tree op1, profile_probability op1_prob = profile_probability::uninitialized (); if (prob.initialized_p ()) { - op0_prob = prob.apply_scale (1, 2); - op1_prob = prob.apply_scale (1, 2) / op0_prob.invert (); + op1_prob = prob; + op0_prob = op1_prob.split (profile_probability::even ()); } if (if_true_label == NULL) { @@ -1120,16 +1118,27 @@ do_compare_rtx_and_jump (rtx op0, rtx op1, enum rtx_code code, int unsignedp, else { - profile_probability first_prob = prob; + profile_probability cprob + = profile_probability::guessed_always (); if (first_code == UNORDERED) - first_prob = profile_probability::guessed_always ().apply_scale - (1, 100); + cprob = cprob.apply_scale (1, 100); else if (first_code == ORDERED) - first_prob = profile_probability::guessed_always ().apply_scale - (99, 100); + cprob = cprob.apply_scale (99, 100); + else + cprob = profile_probability::even (); + /* We want to split: + if (x) goto t; // prob; + into + if (a) goto t; // first_prob; + if (b) goto t; // prob; + such that the overall probability of jumping to t + remains the same and first_prob is prob * cprob. */ if (and_them) { rtx_code_label *dest_label; + prob = prob.invert (); + profile_probability first_prob = prob.split (cprob).invert (); + prob = prob.invert (); /* If we only jump if true, just bypass the second jump. */ if (! if_false_label) { @@ -1143,8 +1152,11 @@ do_compare_rtx_and_jump (rtx op0, rtx op1, enum rtx_code code, int unsignedp, size, dest_label, NULL, first_prob); } else - do_compare_rtx_and_jump (op0, op1, first_code, unsignedp, mode, - size, NULL, if_true_label, first_prob); + { + profile_probability first_prob = prob.split (cprob); + do_compare_rtx_and_jump (op0, op1, first_code, unsignedp, mode, + size, NULL, if_true_label, first_prob); + } } } diff --git a/gcc/profile-count.h b/gcc/profile-count.h index 03e6635f0da..db274f4c5af 100644 --- a/gcc/profile-count.h +++ b/gcc/profile-count.h @@ -410,6 +410,30 @@ public: return *this; } + /* Split *THIS (ORIG) probability into 2 probabilities, such that + the returned one (FIRST) is *THIS * CPROB and *THIS is + adjusted (SECOND) so that FIRST + FIRST.invert () * SECOND + == ORIG. This is useful e.g. when splitting a conditional + branch like: + if (cond) + goto lab; // ORIG probability + into + if (cond1) + goto lab; // FIRST = ORIG * CPROB probability + if (cond2) + goto lab; // SECOND probability + such that the overall probability of jumping to lab remains + the same. CPROB gives the relative probability between the + branches. */ + profile_probability split (const profile_probability &cprob) + { + profile_probability ret = *this * cprob; + /* The following is equivalent to: + *this = cprob.invert () * *this / ret.invert (); */ + *this = (*this - ret) / ret.invert (); + return ret; + } + gcov_type apply (gcov_type val) const { if (*this == profile_probability::uninitialized ()) diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 485079a7cb1..23cef820eea 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2018-01-22 Jakub Jelinek + + PR tree-optimization/83081 + * gcc.dg/predict-8.c: Adjust expected probability. + 2018-01-22 Michael Meissner PR target/83862 diff --git a/gcc/testsuite/gcc.dg/predict-8.c b/gcc/testsuite/gcc.dg/predict-8.c index fa975b3d95f..5578175ec80 100644 --- a/gcc/testsuite/gcc.dg/predict-8.c +++ b/gcc/testsuite/gcc.dg/predict-8.c @@ -8,4 +8,4 @@ int foo(float a, float b) { return 2; } -/* { dg-final { scan-rtl-dump-times "99.0. .guessed" 2 "expand"} } */ +/* { dg-final { scan-rtl-dump-times "65.\[34]. .guessed" 2 "expand"} } */