From 6732373ed28e80cd410f8167c9962910effd12eb Mon Sep 17 00:00:00 2001 From: Peter Bergner Date: Wed, 27 Mar 2019 16:59:15 +0000 Subject: [PATCH] re PR rtl-optimization/89313 (ICE in process_alt_operands, at lra-constraints.c:2962) gcc/ PR rtl-optimization/89313 * function.c (matching_constraint_num): New static function. (match_asm_constraints_1): Use it. Fixup white space and comment. Don't replace inputs with non-matching constraints which conflict with early clobber outputs. gcc/testsuite/ PR rtl-optimization/89313 * gcc.dg/pr89313.c: New test. From-SVN: r269969 --- gcc/ChangeLog | 8 ++++++ gcc/function.c | 48 ++++++++++++++++++++++++++-------- gcc/testsuite/ChangeLog | 5 ++++ gcc/testsuite/gcc.dg/pr89313.c | 26 ++++++++++++++++++ 4 files changed, 76 insertions(+), 11 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/pr89313.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index f8a353d16c0..132af149fe7 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,11 @@ +2019-03-27 Peter Bergner + + PR rtl-optimization/89313 + * function.c (matching_constraint_num): New static function. + (match_asm_constraints_1): Use it. Fixup white space and comment. + Don't replace inputs with non-matching constraints which conflict + with early clobber outputs. + 2019-03-27 Jeff Law diff --git a/gcc/function.c b/gcc/function.c index dc035707c20..bf5ba3d7b73 100644 --- a/gcc/function.c +++ b/gcc/function.c @@ -6395,6 +6395,21 @@ make_pass_thread_prologue_and_epilogue (gcc::context *ctxt) } +/* If CONSTRAINT is a matching constraint, then return its number. + Otherwise, return -1. */ + +static int +matching_constraint_num (const char *constraint) +{ + if (*constraint == '%') + constraint++; + + if (IN_RANGE (*constraint, '0', '9')) + return strtoul (constraint, NULL, 10); + + return -1; +} + /* This mini-pass fixes fall-out from SSA in asm statements that have in-out constraints. Say you start with @@ -6453,14 +6468,10 @@ match_asm_constraints_1 (rtx_insn *insn, rtx *p_sets, int noutputs) rtx input, output; rtx_insn *insns; const char *constraint = ASM_OPERANDS_INPUT_CONSTRAINT (op, i); - char *end; int match, j; - if (*constraint == '%') - constraint++; - - match = strtoul (constraint, &end, 10); - if (end == constraint) + match = matching_constraint_num (constraint); + if (match < 0) continue; gcc_assert (match < noutputs); @@ -6477,14 +6488,14 @@ match_asm_constraints_1 (rtx_insn *insn, rtx *p_sets, int noutputs) /* We can't do anything if the output is also used as input, as we're going to overwrite it. */ for (j = 0; j < ninputs; j++) - if (reg_overlap_mentioned_p (output, RTVEC_ELT (inputs, j))) + if (reg_overlap_mentioned_p (output, RTVEC_ELT (inputs, j))) break; if (j != ninputs) continue; /* Avoid changing the same input several times. For asm ("" : "=mr" (out1), "=mr" (out2) : "0" (in), "1" (in)); - only change in once (to out1), rather than changing it + only change it once (to out1), rather than changing it first to out1 and afterwards to out2. */ if (i > 0) { @@ -6502,6 +6513,9 @@ match_asm_constraints_1 (rtx_insn *insn, rtx *p_sets, int noutputs) end_sequence (); emit_insn_before (insns, insn); + constraint = ASM_OPERANDS_OUTPUT_CONSTRAINT(SET_SRC(p_sets[match])); + bool early_clobber_p = strchr (constraint, '&') != NULL; + /* Now replace all mentions of the input with output. We can't just replace the occurrence in inputs[i], as the register might also be used in some other input (or even in an address of an @@ -6523,7 +6537,14 @@ match_asm_constraints_1 (rtx_insn *insn, rtx *p_sets, int noutputs) value, but different pseudos) where we formerly had only one. With more complicated asms this might lead to reload failures which wouldn't have happen without this pass. So, iterate over - all operands and replace all occurrences of the register used. */ + all operands and replace all occurrences of the register used. + + However, if one or more of the 'input' uses have a non-matching + constraint and the matched output operand is an early clobber + operand, then do not replace the input operand, since by definition + it conflicts with the output operand and cannot share the same + register. See PR89313 for details. */ + for (j = 0; j < noutputs; j++) if (!rtx_equal_p (SET_DEST (p_sets[j]), input) && reg_overlap_mentioned_p (input, SET_DEST (p_sets[j]))) @@ -6531,8 +6552,13 @@ match_asm_constraints_1 (rtx_insn *insn, rtx *p_sets, int noutputs) input, output); for (j = 0; j < ninputs; j++) if (reg_overlap_mentioned_p (input, RTVEC_ELT (inputs, j))) - RTVEC_ELT (inputs, j) = replace_rtx (RTVEC_ELT (inputs, j), - input, output); + { + if (!early_clobber_p + || match == matching_constraint_num + (ASM_OPERANDS_INPUT_CONSTRAINT (op, j))) + RTVEC_ELT (inputs, j) = replace_rtx (RTVEC_ELT (inputs, j), + input, output); + } changed = true; } diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index b2c649cfb3e..472b4ed7c2a 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2019-03-27 Peter Bergner + + PR rtl-optimization/89313 + * gcc.dg/pr89313.c: New test. + 2019-03-26 Jeff Law PR rtl-optimization/87761 diff --git a/gcc/testsuite/gcc.dg/pr89313.c b/gcc/testsuite/gcc.dg/pr89313.c new file mode 100644 index 00000000000..6688323fbde --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr89313.c @@ -0,0 +1,26 @@ +/* PR rtl-optimization/89313 */ +/* { dg-do compile { target aarch64*-*-* arm*-*-* i?86-*-* powerpc*-*-* s390*-*-* x86_64-*-* } } */ +/* { dg-options "-O2" } */ + +#if defined (__aarch64__) +# define REG "x0" +#elif defined (__arm__) +# define REG "r0" +#elif defined (__i386__) +# define REG "%eax" +#elif defined (__powerpc__) +# define REG "r3" +#elif defined (__s390__) +# define REG "0" +#elif defined (__x86_64__) +# define REG "rax" +#endif + +long +bug (long arg) +{ + register long output asm (REG); + long input = arg; + asm ("blah %0, %1, %2" : "=&r" (output) : "r" (input), "0" (input)); + return output; +} -- 2.30.2