https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80966
--- Comment #1 from Segher Boessenkool <segher at gcc dot gnu.org> --- Author: segher Date: Fri Jun 9 03:46:08 2017 New Revision: 249046 URL: https://gcc.gnu.org/viewcvs?rev=249046&root=gcc&view=rev Log: rs6000: Don't add an immediate to r0 (PR80966) If there is a large stack frame the rs6000 -fstack-limit code would calculate the new stack pointer value using two insns (an addis and an addi), with r0 as temporary. Such instructions do not exist. This patch changes add<mode>3 to expand using a different strategy in such cases; to FAIL if there is no way to do it (namely, if the source is r0 and there is no way to get a temporary reg); and it changes rs6000_emit_allocate_stack to assert gen_add3_insn did in fact emit instructions. PR target/80966 * config/rs6000/rs6000.c (rs6000_emit_allocate_stack): Assert that gen_add3_insn did not fail. * config/rs6000/rs6000.md (add<mode>3): If asked to add a constant to r0, construct that number in a temporary reg and add that reg to r0. If asked to put the result in r0 as well, fail. gcc/testsuite/ * gcc.target/powerpc/stack-limit.c: New testcase. Added: trunk/gcc/testsuite/gcc.target/powerpc/stack-limit.c Modified: trunk/gcc/ChangeLog trunk/gcc/config/rs6000/rs6000.c trunk/gcc/config/rs6000/rs6000.md trunk/gcc/testsuite/ChangeLog
