From c7797fd3e8889f7017980672dad06a3df8f4cddf Mon Sep 17 00:00:00 2001 From: Segher Boessenkool Date: Mon, 15 Apr 2019 13:33:29 +0200 Subject: [PATCH] combine: Count auto_inc properly (PR89794) The code that checks if an auto-increment from i0 or i1 is not lost is a bit shaky. The code to check the same for i2 is non-existent, and cannot be implemented in a similar way at all. So, this patch counts all auto-increments, and makes sure we end up with the same number as we started with. This works because we still have a check that we will not duplicate any. We should do this some better way, but not while we are in stage 4. PR rtl-optimization/89794 * combine.c (count_auto_inc): New function. (try_combine): Count how many auto_inc expressions there were in the original instructions. Ensure we have the same number in the new instructions. Remove the code that tried to ensure auto_inc side effects on i1 and i0 are not lost. gcc/testsuite/ PR rtl-optimization/89794 * gcc.dg/torture/pr89794.c: New testcase. From-SVN: r270368 --- ChangeLog | 9 ++++ gcc/combine.c | 60 ++++++++++++++++++-------- gcc/testsuite/ChangeLog | 5 +++ gcc/testsuite/gcc.dg/torture/pr89794.c | 24 +++++++++++ 4 files changed, 80 insertions(+), 18 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/torture/pr89794.c diff --git a/ChangeLog b/ChangeLog index 10ea6676726..2605beb5e96 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,12 @@ +2019-04-15 Segher Boessenkool + + PR rtl-optimization/89794 + * combine.c (count_auto_inc): New function. + (try_combine): Count how many auto_inc expressions there were in the + original instructions. Ensure we have the same number in the new + instructions. Remove the code that tried to ensure auto_inc side + effects on i1 and i0 are not lost. + 2019-04-14 Johannes Pfau * configure.ac: Remove d from unsupported languages on mingw and cygwin. diff --git a/gcc/combine.c b/gcc/combine.c index 91e32c88c88..5616e6b1bac 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -2641,6 +2641,16 @@ is_just_move (rtx x) return (GET_CODE (x) == SET && general_operand (SET_SRC (x), VOIDmode)); } +/* Callback function to count autoincs. */ + +static int +count_auto_inc (rtx, rtx, rtx, rtx, rtx, void *arg) +{ + (*((int *) arg))++; + + return 0; +} + /* Try to combine the insns I0, I1 and I2 into I3. Here I0, I1 and I2 appear earlier than I3. I0 and I1 can be zero; then we combine just I2 into I3, or I1 and I2 into @@ -2706,6 +2716,7 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0, int split_i2i3 = 0; int changed_i3_dest = 0; bool i2_was_move = false, i3_was_move = false; + int n_auto_inc = 0; int maxreg; rtx_insn *temp_insn; @@ -3210,6 +3221,16 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0, return 0; } + /* Count how many auto_inc expressions there were in the original insns; + we need to have the same number in the resulting patterns. */ + + if (i0) + for_each_inc_dec (PATTERN (i0), count_auto_inc, &n_auto_inc); + if (i1) + for_each_inc_dec (PATTERN (i1), count_auto_inc, &n_auto_inc); + for_each_inc_dec (PATTERN (i2), count_auto_inc, &n_auto_inc); + for_each_inc_dec (PATTERN (i3), count_auto_inc, &n_auto_inc); + /* If the set in I2 needs to be kept around, we must make a copy of PATTERN (I2), so that when we substitute I1SRC for I1DEST in PATTERN (I2), we are only substituting for the original I1DEST, not into @@ -3411,18 +3432,11 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0, if (i1 && GET_CODE (newpat) != CLOBBER) { - /* Check that an autoincrement side-effect on I1 has not been lost. - This happens if I1DEST is mentioned in I2 and dies there, and - has disappeared from the new pattern. */ - if ((FIND_REG_INC_NOTE (i1, NULL_RTX) != 0 - && i1_feeds_i2_n - && dead_or_set_p (i2, i1dest) - && !reg_overlap_mentioned_p (i1dest, newpat)) - /* Before we can do this substitution, we must redo the test done - above (see detailed comments there) that ensures I1DEST isn't - mentioned in any SETs in NEWPAT that are field assignments. */ - || !combinable_i3pat (NULL, &newpat, i1dest, NULL_RTX, NULL_RTX, - 0, 0, 0)) + /* Before we can do this substitution, we must redo the test done + above (see detailed comments there) that ensures I1DEST isn't + mentioned in any SETs in NEWPAT that are field assignments. */ + if (!combinable_i3pat (NULL, &newpat, i1dest, NULL_RTX, NULL_RTX, + 0, 0, 0)) { undo_all (); return 0; @@ -3452,12 +3466,8 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0, if (i0 && GET_CODE (newpat) != CLOBBER) { - if ((FIND_REG_INC_NOTE (i0, NULL_RTX) != 0 - && ((i0_feeds_i2_n && dead_or_set_p (i2, i0dest)) - || (i0_feeds_i1_n && dead_or_set_p (i1, i0dest))) - && !reg_overlap_mentioned_p (i0dest, newpat)) - || !combinable_i3pat (NULL, &newpat, i0dest, NULL_RTX, NULL_RTX, - 0, 0, 0)) + if (!combinable_i3pat (NULL, &newpat, i0dest, NULL_RTX, NULL_RTX, + 0, 0, 0)) { undo_all (); return 0; @@ -3478,6 +3488,20 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0, substed_i0 = 1; } + if (n_auto_inc) + { + int new_n_auto_inc = 0; + for_each_inc_dec (newpat, count_auto_inc, &new_n_auto_inc); + + if (n_auto_inc != new_n_auto_inc) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "Number of auto_inc expressions changed\n"); + undo_all (); + return 0; + } + } + /* Fail if an autoincrement side-effect has been duplicated. Be careful to count all the ways that I2SRC and I1SRC can be used. */ if ((FIND_REG_INC_NOTE (i2, NULL_RTX) != 0 diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 5513a934f73..be91be7c11b 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2019-04-15 Segher Boessenkool + + PR rtl-optimization/89794 + * gcc.dg/torture/pr89794.c: New testcase. + 2019-04-15 Richard Biener PR ipa/88936 diff --git a/gcc/testsuite/gcc.dg/torture/pr89794.c b/gcc/testsuite/gcc.dg/torture/pr89794.c new file mode 100644 index 00000000000..91bb0c4138c --- /dev/null +++ b/gcc/testsuite/gcc.dg/torture/pr89794.c @@ -0,0 +1,24 @@ +/* { dg-do run } */ + +typedef unsigned short u16; +typedef unsigned int u32; +typedef unsigned long long u64; + +u32 a, b, c, d; + +u32 foo (u32 f, u32 g, u32 g2, u32 g3, u16 h, u16 i) +{ + (void)g, (void)g2, (void)g3, (void)h; + d = __builtin_bswap64 (i); + __builtin_sub_overflow (0, d, &b); + __builtin_memset (&i, c, 2); + a = 0; + return b + f + i + c; +} + +int main (void) +{ + u32 x = foo (0, 0, 0, 0, 0, 0); + asm ("" :: "r" (x)); + return 0; +} -- 2.30.2