diff options
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/config/i386/i386.c | 38 |
2 files changed, 43 insertions, 0 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 1e4ce3ebfd0..d93fec3b6ca 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2008-09-13 Jan Hubicka <jh@suse.cz> + + * i386.c (ix86_expand_movmem, ix86_expand_movstr): Avoid processing too + many bytes on misalligned blocks. + 2008-09-13 Ralf Wildenhues <Ralf.Wildenhues@gmx.de> * doc/cfg.texi: Fix some typos. diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c index 3662d966361..79531a3d5a1 100644 --- a/gcc/config/i386/i386.c +++ b/gcc/config/i386/i386.c @@ -17222,6 +17222,7 @@ ix86_expand_movmem (rtx dst, rtx src, rtx count_exp, rtx align_exp, int desired_align = 0; enum stringop_alg alg; int dynamic_check; + bool need_zero_guard = false; if (CONST_INT_P (align_exp)) align = INTVAL (align_exp); @@ -17260,9 +17261,11 @@ ix86_expand_movmem (rtx dst, rtx src, rtx count_exp, rtx align_exp, case no_stringop: gcc_unreachable (); case loop: + need_zero_guard = true; size_needed = GET_MODE_SIZE (Pmode); break; case unrolled_loop: + need_zero_guard = true; size_needed = GET_MODE_SIZE (Pmode) * (TARGET_64BIT ? 4 : 2); break; case rep_prefix_8_byte: @@ -17272,7 +17275,10 @@ ix86_expand_movmem (rtx dst, rtx src, rtx count_exp, rtx align_exp, size_needed = 4; break; case rep_prefix_1_byte: + size_needed = 1; + break; case loop_1_byte: + need_zero_guard = true; size_needed = 1; break; } @@ -17350,6 +17356,19 @@ ix86_expand_movmem (rtx dst, rtx src, rtx count_exp, rtx align_exp, dst = change_address (dst, BLKmode, destreg); expand_movmem_prologue (dst, src, destreg, srcreg, count_exp, align, desired_align); + if (need_zero_guard && !count) + { + /* It is possible that we copied enough so the main loop will not + execute. */ + emit_cmp_and_jump_insns (count_exp, + GEN_INT (size_needed), + LTU, 0, counter_mode (count_exp), 1, label); + if (expected_size == -1 + || expected_size < (desired_align - align) / 2 + size_needed) + predict_jump (REG_BR_PROB_BASE * 20 / 100); + else + predict_jump (REG_BR_PROB_BASE * 60 / 100); + } } if (label && size_needed == 1) { @@ -17550,6 +17569,7 @@ ix86_expand_setmem (rtx dst, rtx count_exp, rtx val_exp, rtx align_exp, rtx promoted_val = NULL; bool force_loopy_epilogue = false; int dynamic_check; + bool need_zero_guard = false; if (CONST_INT_P (align_exp)) align = INTVAL (align_exp); @@ -17587,9 +17607,11 @@ ix86_expand_setmem (rtx dst, rtx count_exp, rtx val_exp, rtx align_exp, case no_stringop: gcc_unreachable (); case loop: + need_zero_guard = true; size_needed = GET_MODE_SIZE (Pmode); break; case unrolled_loop: + need_zero_guard = true; size_needed = GET_MODE_SIZE (Pmode) * 4; break; case rep_prefix_8_byte: @@ -17599,7 +17621,10 @@ ix86_expand_setmem (rtx dst, rtx count_exp, rtx val_exp, rtx align_exp, size_needed = 4; break; case rep_prefix_1_byte: + size_needed = 1; + break; case loop_1_byte: + need_zero_guard = true; size_needed = 1; break; } @@ -17675,6 +17700,19 @@ ix86_expand_setmem (rtx dst, rtx count_exp, rtx val_exp, rtx align_exp, dst = change_address (dst, BLKmode, destreg); expand_setmem_prologue (dst, destreg, promoted_val, count_exp, align, desired_align); + if (need_zero_guard && !count) + { + /* It is possible that we copied enough so the main loop will not + execute. */ + emit_cmp_and_jump_insns (count_exp, + GEN_INT (size_needed), + LTU, 0, counter_mode (count_exp), 1, label); + if (expected_size == -1 + || expected_size < (desired_align - align) / 2 + size_needed) + predict_jump (REG_BR_PROB_BASE * 20 / 100); + else + predict_jump (REG_BR_PROB_BASE * 60 / 100); + } } if (label && size_needed == 1) { |