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| author | DJ Delorie <dj@redhat.com> | 2009-07-16 16:07:46 -0400 |
|---|---|---|
| committer | DJ Delorie <dj@gcc.gnu.org> | 2009-07-16 16:07:46 -0400 |
| commit | b3c5a40978985447d8ccf7d583929a4e8a78a91d (patch) | |
| tree | 7781034cea0432cdfc21c30068ff504decdf6798 | |
| parent | a41d064d96aa33de2cbc5ee6bf1f3f9fc76ef528 (diff) | |
| download | gcc-b3c5a40978985447d8ccf7d583929a4e8a78a91d.tar.gz | |
m32c.c (m32c_compare_redundant): Avoid removing compares that may be indirectly affected by previous instructions.
* config/m32c/m32c.c (m32c_compare_redundant): Avoid removing
compares that may be indirectly affected by previous instructions.
From-SVN: r149719
| -rw-r--r-- | gcc/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/config/m32c/m32c.c | 36 |
2 files changed, 40 insertions, 1 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 3e6a75f2a15..173cabf87e9 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2009-07-16 DJ Delorie <dj@redhat.com> + + * config/m32c/m32c.c (m32c_compare_redundant): Avoid removing + compares that may be indirectly affected by previous instructions. + 2009-07-16 Kaveh R. Ghazi <ghazi@caip.rutgers.edu> * builtins.c (do_mpc_arg2): New. diff --git a/gcc/config/m32c/m32c.c b/gcc/config/m32c/m32c.c index 9672dfa718a..46dc4dc6639 100644 --- a/gcc/config/m32c/m32c.c +++ b/gcc/config/m32c/m32c.c @@ -4167,6 +4167,40 @@ m32c_compare_redundant (rtx cmp, rtx *operands) #endif return false; } + + /* Check for comparisons against memory - between volatiles and + aliases, we just can't risk this one. */ + if (GET_CODE (operands[0]) == MEM + || GET_CODE (operands[0]) == MEM) + { +#if DEBUG_CMP + fprintf(stderr, "comparisons with memory:\n"); + debug_rtx(prev); +#endif + return false; + } + + /* Check for PREV changing a register that's used to compute a + value in CMP, even if it doesn't otherwise change flags. */ + if (GET_CODE (operands[0]) == REG + && rtx_referenced_p (SET_DEST (PATTERN (prev)), operands[0])) + { +#if DEBUG_CMP + fprintf(stderr, "sub-value affected, op0:\n"); + debug_rtx(prev); +#endif + return false; + } + if (GET_CODE (operands[1]) == REG + && rtx_referenced_p (SET_DEST (PATTERN (prev)), operands[1])) + { +#if DEBUG_CMP + fprintf(stderr, "sub-value affected, op1:\n"); + debug_rtx(prev); +#endif + return false; + } + } while (pflags == FLAGS_N); #if DEBUG_CMP fprintf(stderr, "previous flag-setting insn:\n"); @@ -4251,7 +4285,7 @@ m32c_output_compare (rtx insn, rtx *operands) } #if DEBUG_CMP - fprintf(stderr, "cbranch: cmp needed: `%s'\n", templ); + fprintf(stderr, "cbranch: cmp needed: `%s'\n", templ + 1); #endif return templ + 1; } |