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| author | Michael Hayes <m.hayes@elec.canterbury.ac.nz> | 2004-01-26 00:31:50 +0000 |
|---|---|---|
| committer | Michael Hayes <m.hayes@gcc.gnu.org> | 2004-01-26 00:31:50 +0000 |
| commit | a026b9d64dfbcdd8efd4ffde6f435274f529765c (patch) | |
| tree | 8befc5c1576f5b27d786d74f3d06ad0efb0c7fac | |
| parent | b6ab76d653319cd1136a4a619d714d45c9ce12f0 (diff) | |
| download | gcc-a026b9d64dfbcdd8efd4ffde6f435274f529765c.zip gcc-a026b9d64dfbcdd8efd4ffde6f435274f529765c.tar.gz gcc-a026b9d64dfbcdd8efd4ffde6f435274f529765c.tar.bz2 | |
* config/c4x/c4x.c (legitimize_operands): Truncate invalid shift counts.
From-SVN: r76610
| -rw-r--r-- | gcc/ChangeLog | 4 | ||||
| -rw-r--r-- | gcc/config/c4x/c4x.c | 13 |
2 files changed, 16 insertions, 1 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 9173a2e..6a4dac9 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,5 +1,9 @@ 2004-01-26 Michael Hayes <m.hayes@elec.canterbury.ac.nz> + * config/c4x/c4x.c (legitimize_operands): Truncate invalid shift counts. + +2004-01-26 Michael Hayes <m.hayes@elec.canterbury.ac.nz> + * config/c4x/c4x.c (c4x_valid_operands): More aggressively reject invalid operand combinations. diff --git a/gcc/config/c4x/c4x.c b/gcc/config/c4x/c4x.c index 31c1e83..db350ce 100644 --- a/gcc/config/c4x/c4x.c +++ b/gcc/config/c4x/c4x.c @@ -3944,7 +3944,7 @@ legitimize_operands (enum rtx_code code, rtx *operands, enum machine_mode mode) /* We can get better code on a C30 if we force constant shift counts into a register. This way they can get hoisted out of loops, - tying up a register, but saving an instruction. The downside is + tying up a register but saving an instruction. The downside is that they may get allocated to an address or index register, and thus we will get a pipeline conflict if there is a nearby indirect address using an address register. @@ -3978,6 +3978,17 @@ legitimize_operands (enum rtx_code code, rtx *operands, enum machine_mode mode) && (GET_CODE (operands[2]) != CONST_INT)) operands[2] = gen_rtx_NEG (mode, negate_rtx (mode, operands[2])); + + /* When the shift count is greater than 32 then the result + can be implementation dependent. We truncate the result to + fit in 5 bits so that we do not emit invalid code when + optimising---such as trying to generate lhu2 with 20021124-1.c. */ + if (((code == ASHIFTRT || code == LSHIFTRT || code == ASHIFT) + && (GET_CODE (operands[2]) == CONST_INT)) + && INTVAL (operands[2]) > (GET_MODE_BITSIZE (mode) - 1)) + operands[2] + = GEN_INT (INTVAL (operands[2]) & (GET_MODE_BITSIZE (mode) - 1)); + return 1; } |