diff options
| -rw-r--r-- | gcc/ChangeLog | 8 | ||||
| -rw-r--r-- | gcc/ifcvt.c | 88 | ||||
| -rw-r--r-- | gcc/testsuite/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.c-torture/execute/20051104-1.c | 17 |
4 files changed, 93 insertions, 25 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index dbe9c080c94..fb378115a8f 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,11 @@ +2005-11-07 Jakub Jelinek <jakub@redhat.com> + + PR rtl-optimization/23567 + * ifcvt.c (noce_mem_write_may_trap_or_fault_p): New function. + (noce_process_if_block): Don't do any optimizations except + if (cond) x = x; if !set_b and write into orig_x may trap + or fault. Remove the MEM_READONLY_P check. + 2005-11-06 Diego Novillo <dnovillo@redhat.com> PR 24670 diff --git a/gcc/ifcvt.c b/gcc/ifcvt.c index d74d9457d7b..da32ab45a71 100644 --- a/gcc/ifcvt.c +++ b/gcc/ifcvt.c @@ -2025,6 +2025,59 @@ noce_operand_ok (rtx op) return ! may_trap_p (op); } +/* Return true if a write into MEM may trap or fault. */ + +static bool +noce_mem_write_may_trap_or_fault_p (rtx mem) +{ + rtx addr; + + if (MEM_READONLY_P (mem)) + return true; + + if (may_trap_or_fault_p (mem)) + return true; + + addr = XEXP (mem, 0); + + /* Call target hook to avoid the effects of -fpic etc.... */ + addr = targetm.delegitimize_address (addr); + + while (addr) + switch (GET_CODE (addr)) + { + case CONST: + case PRE_DEC: + case PRE_INC: + case POST_DEC: + case POST_INC: + case POST_MODIFY: + addr = XEXP (addr, 0); + break; + case LO_SUM: + case PRE_MODIFY: + addr = XEXP (addr, 1); + break; + case PLUS: + if (GET_CODE (XEXP (addr, 1)) == CONST_INT) + addr = XEXP (addr, 0); + else + return false; + break; + case LABEL_REF: + return true; + case SYMBOL_REF: + if (SYMBOL_REF_DECL (addr) + && decl_readonly_section (SYMBOL_REF_DECL (addr), 0)) + return true; + return false; + default: + return false; + } + + return false; +} + /* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it without using conditional execution. Return TRUE if we were successful at converting the block. */ @@ -2136,14 +2189,6 @@ noce_process_if_block (struct ce_if_block * ce_info) if (side_effects_p (x)) return FALSE; - /* If x is a read-only memory, then the program is valid only if we - avoid the store into it. If there are stores on both the THEN and - ELSE arms, then we can go ahead with the conversion; either the - program is broken, or the condition is always false such that the - other memory is selected. */ - if (!set_b && MEM_P (x) && MEM_READONLY_P (x)) - return FALSE; - b = (set_b ? SET_SRC (set_b) : x); /* Only operate on register destinations, and even then avoid extending @@ -2211,23 +2256,16 @@ noce_process_if_block (struct ce_if_block * ce_info) } /* Disallow the "if (...) x = a;" form (with an implicit "else x = x;") - for most optimizations if writing to x may trap, i.e. it's a memory - other than a static var or a stack slot. */ - if (! set_b - && MEM_P (orig_x) - && ! MEM_NOTRAP_P (orig_x) - && rtx_addr_can_trap_p (XEXP (orig_x, 0))) - { - if (HAVE_conditional_move) - { - if (noce_try_cmove (&if_info)) - goto success; - if (! HAVE_conditional_execution - && noce_try_cmove_arith (&if_info)) - goto success; - } - return FALSE; - } + for optimizations if writing to x may trap or fault, i.e. it's a memory + other than a static var or a stack slot, is misaligned on strict + aligned machines or is read-only. + If x is a read-only memory, then the program is valid only if we + avoid the store into it. If there are stores on both the THEN and + ELSE arms, then we can go ahead with the conversion; either the + program is broken, or the condition is always false such that the + other memory is selected. */ + if (!set_b && MEM_P (orig_x) && noce_mem_write_may_trap_or_fault_p (orig_x)) + return FALSE; if (noce_try_move (&if_info)) goto success; diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 0dca65ba811..0ab25393c78 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2005-11-07 Jakub Jelinek <jakub@redhat.com> + + PR rtl-optimization/23567 + * gcc.c-torture/execute/20051104-1.c: New test. + 2005-11-06 Paul Thomas <pault@gcc.gnu.org> PR fortran/24534 diff --git a/gcc/testsuite/gcc.c-torture/execute/20051104-1.c b/gcc/testsuite/gcc.c-torture/execute/20051104-1.c new file mode 100644 index 00000000000..16578778cc6 --- /dev/null +++ b/gcc/testsuite/gcc.c-torture/execute/20051104-1.c @@ -0,0 +1,17 @@ +/* PR rtl-optimization/23567 */ + +struct +{ + int len; + char *name; +} s; + +int +main (void) +{ + s.len = 0; + s.name = ""; + if (s.name [s.len] != 0) + s.name [s.len] = 0; + return 0; +} |
