rs6000: Wrap diff of immediates in const (PR83629)
In various of our 32-bit load_toc patterns we take the difference of
two immediates (labels) as a term to something bigger; but this isn't
canonical RTL, it needs to be wrapped in CONST.
PR target/83629
* config/rs6000/rs6000.md (load_toc_v4_PIC_2, load_toc_v4_PIC_3b,
load_toc_v4_PIC_3c): Wrap const term in CONST RTL.
testsuite/
PR target/83629
* gcc.target/powerpc/pr83629.c: New testcase.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@256432 138bc75d-0d04-0410-961f-82ee72b054a4