diff options
Diffstat (limited to 'gcc/expmed.c')
| -rw-r--r-- | gcc/expmed.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/gcc/expmed.c b/gcc/expmed.c index 16c9bef..bb06536 100644 --- a/gcc/expmed.c +++ b/gcc/expmed.c @@ -4181,6 +4181,29 @@ emit_store_flag (target, code, op0, op1, mode, unsignedp, normalizep) break; } + /* If we are comparing a double-word integer with zero, we can convert + the comparison into one involving a single word. */ + if (GET_MODE_BITSIZE (mode) == BITS_PER_WORD * 2 + && GET_MODE_CLASS (mode) == MODE_INT + && op1 == const0_rtx) + { + if (code == EQ || code == NE) + { + /* Do a logical OR of the two words and compare the result. */ + rtx op0h = gen_highpart (word_mode, op0); + rtx op0l = gen_lowpart (word_mode, op0); + rtx op0both = expand_binop (word_mode, ior_optab, op0h, op0l, + NULL_RTX, unsignedp, OPTAB_DIRECT); + if (op0both != 0) + return emit_store_flag (target, code, op0both, op1, word_mode, + unsignedp, normalizep); + } + else if (code == LT || code == GE) + /* If testing the sign bit, can just test on high word. */ + return emit_store_flag (target, code, gen_highpart (word_mode, op0), + op1, word_mode, unsignedp, normalizep); + } + /* From now on, we won't change CODE, so set ICODE now. */ icode = setcc_gen_code[(int) code]; |