https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121124
Bug ID: 121124
Summary: TI PRU target doesn't seem to use constant table if
address has bit31 set
Product: gcc
Version: 15.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: rqou at berkeley dot edu
Target Milestone: ---
When compiling for the TI PRU target, GCC doesn't seem to generate the expected
SBCO opcode when the address in question has bit31 set. It seems to work
correctly when bit31 is 0.
GCC information:
Using built-in specs.
COLLECT_GCC=pru-gcc
COLLECT_LTO_WRAPPER=/opt/pru/libexec/gcc/pru/15.1.0/lto-wrapper
Target: pru
Configured with: ../../gcc-15.1.0/configure --target=pru --prefix=/opt/pru
--disable-nls --with-newlib --enable-languages=c,c++
--with-gmp=/opt/homebrew/Cellar/gmp/6.3.0
--with-mpfr=/opt/homebrew/Cellar/mpfr/4.2.1
--with-mpc=/opt/homebrew/Cellar/libmpc/1.3.1
Thread model: single
Supported LTO compression algorithms: zlib
gcc version 15.1.0 (GCC)
Minimal test case:
#pragma ctable_entry 30 0x00beef00
void good() {
*(volatile unsigned int *)0x00beef00 = 0xdead;
}
#pragma ctable_entry 31 0x80beef00
void bad() {
*(volatile unsigned int *)0x80beef00 = 0xf00d;
}
Compile using: pru-gcc -v -save-temps -Wextra -Wall -Os -c test.c
Result:
The function `good` uses SBCO as desired, whereas the function `bad` generates
a less-efficient ldi32+SBBO.
