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| author | Richard Stallman <rms@gnu.org> | 1992-11-08 00:10:42 +0000 |
|---|---|---|
| committer | Richard Stallman <rms@gnu.org> | 1992-11-08 00:10:42 +0000 |
| commit | 55f8a64c0fbebdfbfd8c23a42bf9acb6409b4ce0 (patch) | |
| tree | 92446c4050d695e79d6c273b81099ed46cb8e272 | |
| parent | 8843f6e2a93e098c0a488d68b324f16eb7a23186 (diff) | |
| download | gcc-55f8a64c0fbebdfbfd8c23a42bf9acb6409b4ce0.zip gcc-55f8a64c0fbebdfbfd8c23a42bf9acb6409b4ce0.tar.gz gcc-55f8a64c0fbebdfbfd8c23a42bf9acb6409b4ce0.tar.bz2 | |
(gen_int_relational): Handle overflow when incrementing cmp1.
From-SVN: r2714
| -rw-r--r-- | gcc/config/mips/mips.c | 38 |
1 files changed, 27 insertions, 11 deletions
diff --git a/gcc/config/mips/mips.c b/gcc/config/mips/mips.c index 966dd85..09c73fe 100644 --- a/gcc/config/mips/mips.c +++ b/gcc/config/mips/mips.c @@ -1554,20 +1554,21 @@ gen_int_relational (test_code, result, cmp0, cmp1, p_invert) int reverse_regs; /* reverse registers in test */ int invert_const; /* != 0 if invert value if cmp1 is constant */ int invert_reg; /* != 0 if invert value if cmp1 is register */ + int unsignedp; /* != 0 for unsigned comparisons. */ }; static struct cmp_info info[ (int)ITEST_MAX ] = { - { XOR, 0, 65535, 0, 0, 0, 0 }, /* EQ */ - { XOR, 0, 65535, 0, 0, 1, 1 }, /* NE */ - { LT, -32769, 32766, 1, 1, 1, 0 }, /* GT */ - { LT, -32768, 32767, 0, 0, 1, 1 }, /* GE */ - { LT, -32768, 32767, 0, 0, 0, 0 }, /* LT */ - { LT, -32769, 32766, 1, 1, 0, 1 }, /* LE */ - { LTU, -32769, 32766, 1, 1, 1, 0 }, /* GTU */ - { LTU, -32768, 32767, 0, 0, 1, 1 }, /* GEU */ - { LTU, -32768, 32767, 0, 0, 0, 0 }, /* LTU */ - { LTU, -32769, 32766, 1, 1, 0, 1 }, /* LEU */ + { XOR, 0, 65535, 0, 0, 0, 0, 0 }, /* EQ */ + { XOR, 0, 65535, 0, 0, 1, 1, 0 }, /* NE */ + { LT, -32769, 32766, 1, 1, 1, 0, 0 }, /* GT */ + { LT, -32768, 32767, 0, 0, 1, 1, 0 }, /* GE */ + { LT, -32768, 32767, 0, 0, 0, 0, 0 }, /* LT */ + { LT, -32769, 32766, 1, 1, 0, 1, 0 }, /* LE */ + { LTU, -32769, 32766, 1, 1, 1, 0, 1 }, /* GTU */ + { LTU, -32768, 32767, 0, 0, 1, 1, 1 }, /* GEU */ + { LTU, -32768, 32767, 0, 0, 0, 0, 1 }, /* LTU */ + { LTU, -32769, 32766, 1, 1, 0, 1, 1 }, /* LEU */ }; enum internal_test test; @@ -1631,7 +1632,22 @@ gen_int_relational (test_code, result, cmp0, cmp1, p_invert) if (GET_CODE (cmp1) == CONST_INT) { if (p_info->const_add != 0) - cmp1 = GEN_INT (INTVAL (cmp1) + p_info->const_add); + { + HOST_WIDE_INT new = INTVAL (cmp1) + p_info->const_add; + /* If modification of cmp1 caused overflow, + we would get the wrong answer if we follow the usual path; + thus, x > 0xffffffffu would turn into x > 0u. */ + if ((p_info->unsignedp + ? (unsigned HOST_WIDE_INT) new > INTVAL (cmp1) + : new > INTVAL (cmp1)) + != (p_info->const_add > 0)) + /* 1 is the right value in the LE and LEU case. + In the GT and GTU case, *p_invert is already set, + so this is effectively 0. */ + return force_reg (SImode, const1_rtx); + else + cmp1 = GEN_INT (new); + } } else if (p_info->reverse_regs) { |