OpenE2K/gcc
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

(gen_int_relational): Handle overflow when incrementing cmp1.

Browse Source 
From-SVN: r2714
This commit is contained in:
Richard Stallman 1992-11-08 00:10:42 +00:00
parent 8843f6e2a9
commit 55f8a64c0f
1 changed files with 27 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
gcc/config/mips/mips.c
View File

@ -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)
{