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Jan Hubicka <hubicka@freesoft.cz>

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Jan Hubicka <hubicka@freesoft.cz>
        * i386.md: Do not output mov %0,reg on AMD K6.

From-SVN: r26406
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Jan Hubicka 1999-04-13 16:15:46 +02:00 committed by Richard Henderson
parent b81194219b
commit 0ffc4dca8e
2 changed files with 18 additions and 4 deletions
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4
gcc/ChangeLog
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@ -1,3 +1,7 @@
Tue Apr 13 14:14:06 1999 Jan Hubicka <hubicka@freesoft.cz>
* i386.md: Do not output mov %0,reg on AMD K6.
Tue Apr 13 12:14:07 1999 Dave Brolley <brolley@cygnus.com>
* cppinit.c (cpp_start_read): Fix buffer overwrite.

18
gcc/config/i386/i386.md
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@ -983,8 +983,13 @@
"*
{
rtx link;
if ((ix86_cpu != PROCESSOR_K6 || optimize_size)
&& operands[1] == const0_rtx && REG_P (operands[0]))
/* Use of xor was disabled for AMD K6 as recommended by the Optimization
Manual. My test shows, that this generally hurts the performance, because
mov is longer and takes longer to decode and decoding is the main
bottleneck of K6 when executing GCC code. */
if (operands[1] == const0_rtx && REG_P (operands[0]))
return AS2 (xor%L0,%0,%0);
if (operands[1] == const1_rtx
@ -1111,8 +1116,13 @@
"*
{
rtx link;
if ((ix86_cpu != PROCESSOR_K6 || optimize_size)
&& operands[1] == const0_rtx && REG_P (operands[0]))
/* Use of xor was disabled for AMD K6 as recommended by the Optimization
Manual. My test shows, that this generally hurts the performance, because
mov is longer and takes longer to decode and decoding is the main
bottleneck of K6 when executing GCC code. */
if (operands[1] == const0_rtx && REG_P (operands[0]))
return AS2 (xor%W0,%0,%0);
if (operands[1] == const1_rtx