diff options
author | Nathan Froyd <froydnj@codesourcery.com> | 2010-10-20 20:15:07 +0000 |
---|---|---|
committer | Nathan Froyd <froydnj@gcc.gnu.org> | 2010-10-20 20:15:07 +0000 |
commit | 582346ed66a6dc53e22426ae66d01d935e3595bc (patch) | |
tree | 6a8239d64dc65925957fb1ccbe0060db0f992701 /gcc/ifcvt.c | |
parent | ab177ad53847e22cc5aaf10ffc319060c633cc4f (diff) | |
download | gcc-582346ed66a6dc53e22426ae66d01d935e3595bc.zip gcc-582346ed66a6dc53e22426ae66d01d935e3595bc.tar.gz gcc-582346ed66a6dc53e22426ae66d01d935e3595bc.tar.bz2 |
ifcvt.c (noce_emit_cmove): If both of the values are SUBREGs...
* ifcvt.c (noce_emit_cmove): If both of the values are SUBREGs, try
emitting the conditional move in the inner mode of the SUBREG.
From-SVN: r165735
Diffstat (limited to 'gcc/ifcvt.c')
-rw-r--r-- | gcc/ifcvt.c | 63 |
1 files changed, 59 insertions, 4 deletions
diff --git a/gcc/ifcvt.c b/gcc/ifcvt.c index eb96182..15f76e3 100644 --- a/gcc/ifcvt.c +++ b/gcc/ifcvt.c @@ -1337,6 +1337,9 @@ static rtx noce_emit_cmove (struct noce_if_info *if_info, rtx x, enum rtx_code code, rtx cmp_a, rtx cmp_b, rtx vfalse, rtx vtrue) { + rtx target; + int unsignedp; + /* If earliest == jump, try to build the cmove insn directly. This is helpful when combine has created some complex condition (like for alpha's cmovlbs) that we can't hope to regenerate @@ -1371,10 +1374,62 @@ noce_emit_cmove (struct noce_if_info *if_info, rtx x, enum rtx_code code, return NULL_RTX; #if HAVE_conditional_move - return emit_conditional_move (x, code, cmp_a, cmp_b, VOIDmode, - vtrue, vfalse, GET_MODE (x), - (code == LTU || code == GEU - || code == LEU || code == GTU)); + unsignedp = (code == LTU || code == GEU + || code == LEU || code == GTU); + + target = emit_conditional_move (x, code, cmp_a, cmp_b, VOIDmode, + vtrue, vfalse, GET_MODE (x), + unsignedp); + if (target) + return target; + + /* We might be faced with a situation like: + + x = (reg:M TARGET) + vtrue = (subreg:M (reg:N VTRUE) BYTE) + vfalse = (subreg:M (reg:N VFALSE) BYTE) + + We can't do a conditional move in mode M, but it's possible that we + could do a conditional move in mode N instead and take a subreg of + the result. + + If we can't create new pseudos, though, don't bother. */ + if (reload_completed) + return NULL_RTX; + + if (GET_CODE (vtrue) == SUBREG && GET_CODE (vfalse) == SUBREG) + { + rtx reg_vtrue = SUBREG_REG (vtrue); + rtx reg_vfalse = SUBREG_REG (vfalse); + unsigned int byte_vtrue = SUBREG_BYTE (vtrue); + unsigned int byte_vfalse = SUBREG_BYTE (vfalse); + rtx promoted_target; + + if (GET_MODE (reg_vtrue) != GET_MODE (reg_vfalse) + || byte_vtrue != byte_vfalse + || (SUBREG_PROMOTED_VAR_P (vtrue) + != SUBREG_PROMOTED_VAR_P (vfalse)) + || (SUBREG_PROMOTED_UNSIGNED_P (vtrue) + != SUBREG_PROMOTED_UNSIGNED_P (vfalse))) + return NULL_RTX; + + promoted_target = gen_reg_rtx (GET_MODE (reg_vtrue)); + + target = emit_conditional_move (promoted_target, code, cmp_a, cmp_b, + VOIDmode, reg_vtrue, reg_vfalse, + GET_MODE (reg_vtrue), unsignedp); + /* Nope, couldn't do it in that mode either. */ + if (!target) + return NULL_RTX; + + target = gen_rtx_SUBREG (GET_MODE (vtrue), promoted_target, byte_vtrue); + SUBREG_PROMOTED_VAR_P (target) = SUBREG_PROMOTED_VAR_P (vtrue); + SUBREG_PROMOTED_UNSIGNED_SET (target, SUBREG_PROMOTED_UNSIGNED_P (vtrue)); + emit_move_insn (x, target); + return x; + } + else + return NULL_RTX; #else /* We'll never get here, as noce_process_if_block doesn't call the functions involved. Ifdef code, however, should be discouraged |