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| author | Richard Kenner <kenner@gcc.gnu.org> | 1993-12-23 18:27:51 -0500 |
|---|---|---|
| committer | Richard Kenner <kenner@gcc.gnu.org> | 1993-12-23 18:27:51 -0500 |
| commit | c0a085741f84e1032be54981c426169f9bd5f7be (patch) | |
| tree | a1298e812920bc767038649b59c62afc0bf8ca87 /gcc | |
| parent | cfc327a27190a0e4c537e7e1f9ab15db359667cf (diff) | |
| download | gcc-c0a085741f84e1032be54981c426169f9bd5f7be.zip gcc-c0a085741f84e1032be54981c426169f9bd5f7be.tar.gz gcc-c0a085741f84e1032be54981c426169f9bd5f7be.tar.bz2 | |
(expand_mult): Preserve useful sub-expressions when
expanding a synthesized mult.
From-SVN: r6287
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/expmed.c | 25 |
1 files changed, 15 insertions, 10 deletions
diff --git a/gcc/expmed.c b/gcc/expmed.c index 69c08d5..4c06fb4 100644 --- a/gcc/expmed.c +++ b/gcc/expmed.c @@ -2153,9 +2153,11 @@ expand_mult (mode, op0, op1, target, unsignedp) for (opno = 1; opno < alg.ops; opno++) { int log = alg.log[opno]; - rtx shift_subtarget = preserve_subexpressions_p () ? 0 : accum; + int preserve = preserve_subexpressions_p (); + rtx shift_subtarget = preserve ? 0 : accum; rtx add_target = opno == alg.ops - 1 && target != 0 ? target : 0; - + rtx accum_target = preserve ? 0 : accum; + switch (alg.op[opno]) { case alg_shift: @@ -2168,7 +2170,7 @@ expand_mult (mode, op0, op1, target, unsignedp) tem = expand_shift (LSHIFT_EXPR, mode, op0, build_int_2 (log, 0), NULL_RTX, 0); accum = force_operand (gen_rtx (PLUS, mode, accum, tem), - add_target ? add_target : accum); + add_target ? add_target : accum_target); val_so_far += (HOST_WIDE_INT) 1 << log; break; @@ -2176,23 +2178,25 @@ expand_mult (mode, op0, op1, target, unsignedp) tem = expand_shift (LSHIFT_EXPR, mode, op0, build_int_2 (log, 0), NULL_RTX, 0); accum = force_operand (gen_rtx (MINUS, mode, accum, tem), - add_target ? add_target : accum); + add_target ? add_target : accum_target); val_so_far -= (HOST_WIDE_INT) 1 << log; break; case alg_add_t2_m: accum = expand_shift (LSHIFT_EXPR, mode, accum, - build_int_2 (log, 0), accum, 0); + build_int_2 (log, 0), shift_subtarget, + 0); accum = force_operand (gen_rtx (PLUS, mode, accum, op0), - add_target ? add_target : accum); + add_target ? add_target : accum_target); val_so_far = (val_so_far << log) + 1; break; case alg_sub_t2_m: accum = expand_shift (LSHIFT_EXPR, mode, accum, - build_int_2 (log, 0), accum, 0); + build_int_2 (log, 0), shift_subtarget, + 0); accum = force_operand (gen_rtx (MINUS, mode, accum, op0), - add_target ? add_target : accum); + add_target ? add_target : accum_target); val_so_far = (val_so_far << log) - 1; break; @@ -2200,7 +2204,7 @@ expand_mult (mode, op0, op1, target, unsignedp) tem = expand_shift (LSHIFT_EXPR, mode, accum, build_int_2 (log, 0), NULL_RTX, 0); accum = force_operand (gen_rtx (PLUS, mode, accum, tem), - add_target ? add_target : accum); + add_target ? add_target : accum_target); val_so_far += val_so_far << log; break; @@ -2208,7 +2212,8 @@ expand_mult (mode, op0, op1, target, unsignedp) tem = expand_shift (LSHIFT_EXPR, mode, accum, build_int_2 (log, 0), NULL_RTX, 0); accum = force_operand (gen_rtx (MINUS, mode, tem, accum), - add_target ? add_target : tem); + (add_target ? add_target + : preserve ? 0 : tem)); val_so_far = (val_so_far << log) - val_so_far; break; |