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Fixed the cc65 code that optimizes 16-bit compares when the high bytes are known to be equal.

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Only the low bytes are compared.  Originally, signed 16-bit compares were optimized into signed 8-bit compares.  But, the sign bits are in the high bytes; and, they're equal.  Therefore, the low bytes always must be compared as unsigned numbers.
Fixes #1348.
This commit is contained in:
Greg King
2020-12-24 12:27:09 -05:00
parent 0f4cb443b4
commit b2c1a77bb3
3 changed files with 37 additions and 77 deletions
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8
test/misc/Makefile
View File

@@ -117,14 +117,6 @@ $(WORKDIR)/endless.$1.$2.prg: endless.c | $(WORKDIR)
$(LD65) -t sim$2 -o $$@ $$(@:.prg=.o) sim$2.lib $(NULLERR)
$(NOT) $(SIM65) $(SIM65FLAGS) $$@ $(NULLOUT) $(NULLERR)
# this one fails when optimization are enabled
$(WORKDIR)/bug1348.$1.$2.prg: bug1348.c | $(WORKDIR)
$(if $(QUIET),echo misc/bug1348.$1.$2.prg)
$(CC65) -Osr -t sim$2 -$1 -o $$(@:.prg=.s) $$< $(NULLERR)
$(CA65) -t sim$2 -o $$(@:.prg=.o) $$(@:.prg=.s) $(NULLERR)
$(LD65) -t sim$2 -o $$@ $$(@:.prg=.o) sim$2.lib $(NULLERR)
$(NOT) $(SIM65) $(SIM65FLAGS) $$@ $(NULLOUT) $(NULLERR)
# these need reference data that can't be generated by a host-compiled program,
# in a useful way
$(WORKDIR)/limits.$1.$2.prg: limits.c $(ISEQUAL) | $(WORKDIR)

28
test/misc/bug1348.c → test/val/bug1348.c
View File

@@ -1,27 +1,26 @@
/* bug#1348, wrongly optimized integer promotion in comparison */
/* bug #1348, wrongly optimized integer promotion in comparison */
#include <stdio.h>
int notrandtab[] = {
static const int notrandtab[] = {
0xffff, 0x7fff, 0x3fff, 0x1fff,
0x0fff, 0x07ff, 0x03ff, 0x01ff,
0x00ff, 0x007f, 0x003f, 0x001f,
0x000f, 0x0007, 0x0003, 0x0001
};
unsigned char notrandcount = 0;
static unsigned char notrandcount = 0;
int notrand(void)
static int notrand(void)
{
return notrandtab[notrandcount & 0x0f];
}
unsigned char n1, n2;
unsigned char i, ii, s;
unsigned char err = 0;
static unsigned char n1, n2;
static unsigned char i, ii, s;
static unsigned char err = 0;
unsigned char cmptab[] = {
static const unsigned char cmptab[] = {
0xff, 0x7f, 0x3f, 0x1f,
0x0f, 0x07, 0x03, 0x01,
0x80, 0x40, 0x20, 0x10,
@@ -40,13 +39,14 @@ int main(void)
if ((notrand() & 0xffu) > s) {
n2 = 1;
}
printf("%5d>%3d %d(%02x) %d(%02x) %s\n",
notrandtab[notrandcount & 0x0f], s,
printf("%5d > %3d %u(%02x) %u(%02x) %s\n",
notrandtab[i], s,
n1, (notrand() & 0xff),
n2, (notrand() & 0xffu),
n1 == n2 ? "=" : "!="
);
if (n1 != n2) err = 1;
n1 == n2 ? "=" : "!=");
if (n1 != n2) {
err = 1;
}
notrandcount++;
}
}