From 8fceae614f031382bc1fa39f94c7d928b5d81f4e Mon Sep 17 00:00:00 2001 From: Thomas Preud'homme Date: Fri, 24 Apr 2015 04:49:34 +0000 Subject: [PATCH] re PR rtl-optimization/34503 (Issues with constant/copy propagation implementation in gcse.c) 2015-04-24 Thomas Preud'homme Steven Bosscher gcc/ PR rtl-optimization/34503 * cprop.c (cprop_reg_p): New. (hash_scan_set): Use above function to check if register can be propagated. (find_avail_set): Return up to two sets, one whose source is a register and one whose source is a constant. Sets are returned in an array passed as parameter rather than as a return value. (cprop_insn): Use a do while loop rather than a goto. Try each of the sets returned by find_avail_set, starting with the one whose source is a constant. Use cprop_reg_p to check if register can be propagated. (do_local_cprop): Use cprop_reg_p to check if register can be propagated. (implicit_set_cond_p): Likewise. gcc/testsuite/ PR rtl-optimization/34503 * gcc.target/arm/pr64616.c: New file. Co-Authored-By: Steven Bosscher From-SVN: r222398 --- gcc/ChangeLog | 17 +++++ gcc/cprop.c | 128 ++++++++++++++++----------------- gcc/testsuite/ChangeLog | 6 ++ gcc/testsuite/gcc.target/arm/pr64616.c | 14 ++++ 4 files changed, 101 insertions(+), 64 deletions(-) create mode 100644 gcc/testsuite/gcc.target/arm/pr64616.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 2eaacfd..7f2d944 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,20 @@ +2015-04-24 Thomas Preud'homme + Steven Bosscher + + PR rtl-optimization/34503 + * cprop.c (cprop_reg_p): New. + (hash_scan_set): Use above function to check if register can be + propagated. + (find_avail_set): Return up to two sets, one whose source is a + register and one whose source is a constant. Sets are returned in an + array passed as parameter rather than as a return value. + (cprop_insn): Use a do while loop rather than a goto. Try each of the + sets returned by find_avail_set, starting with the one whose source is + a constant. Use cprop_reg_p to check if register can be propagated. + (do_local_cprop): Use cprop_reg_p to check if register can be + propagated. + (implicit_set_cond_p): Likewise. + 2015-04-23 Jan Hubicka * ipa-icf.c (sem_function::equals_wpa): Compare thunk info. diff --git a/gcc/cprop.c b/gcc/cprop.c index 0103686..845b644 100644 --- a/gcc/cprop.c +++ b/gcc/cprop.c @@ -285,6 +285,15 @@ cprop_constant_p (const_rtx x) return CONSTANT_P (x) && (GET_CODE (x) != CONST || shared_const_p (x)); } +/* Determine whether the rtx X should be treated as a register that can + be propagated. Any pseudo-register is fine. */ + +static bool +cprop_reg_p (const_rtx x) +{ + return REG_P (x) && !HARD_REGISTER_P (x); +} + /* Scan SET present in INSN and add an entry to the hash TABLE. IMPLICIT is true if it's an implicit set, false otherwise. */ @@ -295,8 +304,7 @@ hash_scan_set (rtx set, rtx_insn *insn, struct hash_table_d *table, rtx src = SET_SRC (set); rtx dest = SET_DEST (set); - if (REG_P (dest) - && ! HARD_REGISTER_P (dest) + if (cprop_reg_p (dest) && reg_available_p (dest, insn) && can_copy_p (GET_MODE (dest))) { @@ -321,9 +329,8 @@ hash_scan_set (rtx set, rtx_insn *insn, struct hash_table_d *table, src = XEXP (note, 0), set = gen_rtx_SET (VOIDmode, dest, src); /* Record sets for constant/copy propagation. */ - if ((REG_P (src) + if ((cprop_reg_p (src) && src != dest - && ! HARD_REGISTER_P (src) && reg_available_p (src, insn)) || cprop_constant_p (src)) insert_set_in_table (dest, src, insn, table, implicit); @@ -821,15 +828,15 @@ try_replace_reg (rtx from, rtx to, rtx_insn *insn) return success; } -/* Find a set of REGNOs that are available on entry to INSN's block. Return - NULL no such set is found. */ +/* Find a set of REGNOs that are available on entry to INSN's block. If found, + SET_RET[0] will be assigned a set with a register source and SET_RET[1] a + set with a constant source. If not found the corresponding entry is set to + NULL. */ -static struct cprop_expr * -find_avail_set (int regno, rtx_insn *insn) +static void +find_avail_set (int regno, rtx_insn *insn, struct cprop_expr *set_ret[2]) { - /* SET1 contains the last set found that can be returned to the caller for - use in a substitution. */ - struct cprop_expr *set1 = 0; + set_ret[0] = set_ret[1] = NULL; /* Loops are not possible here. To get a loop we would need two sets available at the start of the block containing INSN. i.e. we would @@ -869,8 +876,10 @@ find_avail_set (int regno, rtx_insn *insn) If the source operand changed, we may still use it for the next iteration of this loop, but we may not use it for substitutions. */ - if (cprop_constant_p (src) || reg_not_set_p (src, insn)) - set1 = set; + if (cprop_constant_p (src)) + set_ret[1] = set; + else if (reg_not_set_p (src, insn)) + set_ret[0] = set; /* If the source of the set is anything except a register, then we have reached the end of the copy chain. */ @@ -881,10 +890,6 @@ find_avail_set (int regno, rtx_insn *insn) and see if we have an available copy into SRC. */ regno = REGNO (src); } - - /* SET1 holds the last set that was available and anticipatable at - INSN. */ - return set1; } /* Subroutine of cprop_insn that tries to propagate constants into @@ -1048,40 +1053,40 @@ cprop_insn (rtx_insn *insn) int changed = 0, changed_this_round; rtx note; -retry: - changed_this_round = 0; - reg_use_count = 0; - note_uses (&PATTERN (insn), find_used_regs, NULL); - - /* We may win even when propagating constants into notes. */ - note = find_reg_equal_equiv_note (insn); - if (note) - find_used_regs (&XEXP (note, 0), NULL); - - for (i = 0; i < reg_use_count; i++) + do { - rtx reg_used = reg_use_table[i]; - unsigned int regno = REGNO (reg_used); - rtx src; - struct cprop_expr *set; + changed_this_round = 0; + reg_use_count = 0; + note_uses (&PATTERN (insn), find_used_regs, NULL); - /* If the register has already been set in this block, there's - nothing we can do. */ - if (! reg_not_set_p (reg_used, insn)) - continue; + /* We may win even when propagating constants into notes. */ + note = find_reg_equal_equiv_note (insn); + if (note) + find_used_regs (&XEXP (note, 0), NULL); - /* Find an assignment that sets reg_used and is available - at the start of the block. */ - set = find_avail_set (regno, insn); - if (! set) - continue; + for (i = 0; i < reg_use_count; i++) + { + rtx reg_used = reg_use_table[i]; + unsigned int regno = REGNO (reg_used); + rtx src_cst = NULL, src_reg = NULL; + struct cprop_expr *set[2]; - src = set->src; + /* If the register has already been set in this block, there's + nothing we can do. */ + if (! reg_not_set_p (reg_used, insn)) + continue; - /* Constant propagation. */ - if (cprop_constant_p (src)) - { - if (constprop_register (reg_used, src, insn)) + /* Find an assignment that sets reg_used and is available + at the start of the block. */ + find_avail_set (regno, insn, set); + if (set[0]) + src_reg = set[0]->src; + if (set[1]) + src_cst = set[1]->src; + + /* Constant propagation. */ + if (src_cst && cprop_constant_p (src_cst) + && constprop_register (reg_used, src_cst, insn)) { changed_this_round = changed = 1; global_const_prop_count++; @@ -1091,18 +1096,16 @@ retry: "GLOBAL CONST-PROP: Replacing reg %d in ", regno); fprintf (dump_file, "insn %d with constant ", INSN_UID (insn)); - print_rtl (dump_file, src); + print_rtl (dump_file, src_cst); fprintf (dump_file, "\n"); } if (insn->deleted ()) return 1; } - } - else if (REG_P (src) - && REGNO (src) >= FIRST_PSEUDO_REGISTER - && REGNO (src) != regno) - { - if (try_replace_reg (reg_used, src, insn)) + /* Copy propagation. */ + else if (src_reg && cprop_reg_p (src_reg) + && REGNO (src_reg) != regno + && try_replace_reg (reg_used, src_reg, insn)) { changed_this_round = changed = 1; global_copy_prop_count++; @@ -1111,7 +1114,7 @@ retry: fprintf (dump_file, "GLOBAL COPY-PROP: Replacing reg %d in insn %d", regno, INSN_UID (insn)); - fprintf (dump_file, " with reg %d\n", REGNO (src)); + fprintf (dump_file, " with reg %d\n", REGNO (src_reg)); } /* The original insn setting reg_used may or may not now be @@ -1121,12 +1124,10 @@ retry: and made things worse. */ } } - - /* If try_replace_reg simplified the insn, the regs found - by find_used_regs may not be valid anymore. Start over. */ - if (changed_this_round) - goto retry; } + /* If try_replace_reg simplified the insn, the regs found by find_used_regs + may not be valid anymore. Start over. */ + while (changed_this_round); if (changed && DEBUG_INSN_P (insn)) return 0; @@ -1189,7 +1190,7 @@ do_local_cprop (rtx x, rtx_insn *insn) /* Rule out USE instructions and ASM statements as we don't want to change the hard registers mentioned. */ if (REG_P (x) - && (REGNO (x) >= FIRST_PSEUDO_REGISTER + && (cprop_reg_p (x) || (GET_CODE (PATTERN (insn)) != USE && asm_noperands (PATTERN (insn)) < 0))) { @@ -1205,7 +1206,7 @@ do_local_cprop (rtx x, rtx_insn *insn) if (cprop_constant_p (this_rtx)) newcnst = this_rtx; - if (REG_P (this_rtx) && REGNO (this_rtx) >= FIRST_PSEUDO_REGISTER + if (cprop_reg_p (this_rtx) /* Don't copy propagate if it has attached REG_EQUIV note. At this point this only function parameters should have REG_EQUIV notes and if the argument slot is used somewhere @@ -1326,9 +1327,8 @@ implicit_set_cond_p (const_rtx cond) if (GET_CODE (cond) != EQ && GET_CODE (cond) != NE) return false; - /* The first operand of COND must be a pseudo-reg. */ - if (! REG_P (XEXP (cond, 0)) - || HARD_REGISTER_P (XEXP (cond, 0))) + /* The first operand of COND must be a register we can propagate. */ + if (!cprop_reg_p (XEXP (cond, 0))) return false; /* The second operand of COND must be a suitable constant. */ diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index ba700fc..bbc0b24 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,9 @@ +2015-04-24 Thomas Preud'homme + Steven Bosscher + + PR rtl-optimization/34503 + * gcc.target/arm/pr64616.c: New file. + 2015-04-24 Bin Cheng * gcc.target/arm/pr42172-1.c: Check str instead of ldr. diff --git a/gcc/testsuite/gcc.target/arm/pr64616.c b/gcc/testsuite/gcc.target/arm/pr64616.c new file mode 100644 index 0000000..c686ffa --- /dev/null +++ b/gcc/testsuite/gcc.target/arm/pr64616.c @@ -0,0 +1,14 @@ +/* { dg-do compile } */ +/* { dg-options "-O2" } */ + +int f (int); +unsigned int glob; + +void +g () +{ + while (f (glob)); + glob = 5; +} + +/* { dg-final { scan-assembler-times "ldr" 2 } } */ -- 2.7.4