static volatile bool arg1__Bool_1475 = true;
	volatile const static uint_least8_t arg2_char_1479 = 'a';
	printf(  " \t %s %d \n " , "" ,  arg1__Bool_1475 < arg2_char_1479  );
 

gives 0, not 1, on GNU C version 3.3 20030304 (Apple Computer, Inc. build 1495).
Originally found in C99 mode, but also with default flags.
gcc version 2.96 20000731 (Red Hat Linux 7.2 2.96-112.7.2) behaves as expected.
(The extra %s and empty string are for alignment issues on another platform.)



Commands:
gcc ../c/noerror/bugfiles/gcc_bool_bug.c

 a.out 
  1 < 97 ( arg1__Bool_1475 < arg2_char_1479 ) : 
          0 


Full source:

#include <stdio.h>
#include <stdbool.h>
#include <stdint.h>


 int main()	{
//...
	static volatile bool arg1__Bool_1475 = true;
//...
	volatile const static uint_least8_t arg2_char_1479 = 'a';
	printf(  " %s %d" , "" , arg1__Bool_1475  );
	printf(  "%s < %d ( arg1__Bool_1475 < arg2_char_1479 ) : \n " , "" , arg2_char_1479  );
	printf(  " \t %s %d \n " , "" ,  arg1__Bool_1475 < arg2_char_1479  );
//...
	return 42;
}


Pre-processed file to follow, once I figure out how; here's the session:

gcc -v -save-temps ../c/noerror/bugfiles/gcc_bool_bug.c
Reading specs from /usr/libexec/gcc/darwin/ppc/3.3/specs
Thread model: posix
gcc version 3.3 20030304 (Apple Computer, Inc. build 1495)
 /usr/libexec/gcc/darwin/ppc/3.3/cc1 -E -quiet -v -D__GNUC__=3 -D__GNUC_MINOR__=3 
-D__GNUC_PATCHLEVEL__=0 -D__APPLE_CC__=1495 -D__DYNAMIC__ ../c/noerror/bugfiles/
gcc_bool_bug.c -fPIC gcc_bool_bug.i
ignoring nonexistent directory "/usr/ppc-darwin/include"
ignoring nonexistent directory "/Local/Library/Frameworks"
#include "..." search starts here:
#include <...> search starts here:
 /usr/local/include
 /usr/include/gcc/darwin/3.3
 /usr/include
End of search list.
Framework search starts here:
 /System/Library/Frameworks
 /Library/Frameworks
End of framework search list.
 /usr/libexec/gcc/darwin/ppc/3.3/cc1 -fpreprocessed gcc_bool_bug.i -fPIC -quiet -dumpbase 
gcc_bool_bug.c -auxbase gcc_bool_bug -version -o gcc_bool_bug.s
GNU C version 3.3 20030304 (Apple Computer, Inc. build 1495) (ppc-darwin)
        compiled by GNU C version 3.3 20030304 (Apple Computer, Inc. build 1495).
GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=131072
 /usr/libexec/gcc/darwin/ppc/as -arch ppc -o gcc_bool_bug.o gcc_bool_bug.s
 ld -arch ppc -dynamic -o a.out -lcrt1.o -lcrt2.o -L/usr/lib/gcc/darwin/3.3 -L/usr/lib/gcc/darwin -L/
usr/libexec/gcc/darwin/ppc/3.3/../../.. gcc_bool_bug.o -lgcc -lSystem |
 c++filt3