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| author | Segher Boessenkool <segher@kernel.crashing.org> | 2017-11-28 02:28:57 +0100 |
|---|---|---|
| committer | Segher Boessenkool <segher@gcc.gnu.org> | 2017-11-28 02:28:57 +0100 |
| commit | b8adcbd9236598e066fba8e8e31a2e2d40521698 (patch) | |
| tree | e4a556655ee698d12a0b865909e8cbb89dcd522b /gcc | |
| parent | fd8bf76c908297f96f240954c43732579bb95105 (diff) | |
| download | gcc-b8adcbd9236598e066fba8e8e31a2e2d40521698.zip gcc-b8adcbd9236598e066fba8e8e31a2e2d40521698.tar.gz gcc-b8adcbd9236598e066fba8e8e31a2e2d40521698.tar.bz2 | |
rs6000: Improve comparison rtx_cost (PR81288)
The current rs6000 rtx_cost for comparisons against 0 is very high if
TARGET_ISEL && !TARGET_MFCRF, much higher than for reg-reg comparisons,
much higher than a load of 0 and such a reg-reg-comparison. This leads
to infinite recursion in CSE (see PR81288).
This patch removes the too-high cost, also simplifying this code.
PR 81288/target
* config/rs6000/rs6000.c (rs6000_rtx_costs): Do not handle
TARGET_ISEL && !TARGET_MFCRF differently. Simplify code.
From-SVN: r255188
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 6 | ||||
| -rw-r--r-- | gcc/config/rs6000/rs6000.c | 23 |
2 files changed, 12 insertions, 17 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index d3b2f5b..fe6b562 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2017-11-28 Segher Boessenkool <segher@kernel.crashing.org> + + PR 81288/target + * config/rs6000/rs6000.c (rs6000_rtx_costs): Do not handle + TARGET_ISEL && !TARGET_MFCRF differently. Simplify code. + 2017-11-27 Segher Boessenkool <segher@kernel.crashing.org> * config/rs6000/rs6000.md (<code><GPR:mode><GPR2:mode>2_isel): Change diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c index 4df87ea..551d9c4 100644 --- a/gcc/config/rs6000/rs6000.c +++ b/gcc/config/rs6000/rs6000.c @@ -34889,14 +34889,16 @@ rs6000_rtx_costs (rtx x, machine_mode mode, int outer_code, *total = COSTS_N_INSNS (1); return true; } + /* FALLTHRU */ + + case GT: + case LT: + case UNORDERED: if (outer_code == SET) { if (XEXP (x, 1) == const0_rtx) { - if (TARGET_ISEL && !TARGET_MFCRF) - *total = COSTS_N_INSNS (8); - else - *total = COSTS_N_INSNS (2); + *total = COSTS_N_INSNS (2); return true; } else @@ -34905,19 +34907,6 @@ rs6000_rtx_costs (rtx x, machine_mode mode, int outer_code, return false; } } - /* FALLTHRU */ - - case GT: - case LT: - case UNORDERED: - if (outer_code == SET && (XEXP (x, 1) == const0_rtx)) - { - if (TARGET_ISEL && !TARGET_MFCRF) - *total = COSTS_N_INSNS (8); - else - *total = COSTS_N_INSNS (2); - return true; - } /* CC COMPARE. */ if (outer_code == COMPARE) { |