Tested on GCC 8 and 9.
Bootstrapped/regtested on x86_64-linux, ok for trunk?
2019-07-23 Matthew Beliveau <mbeli...@redhat.com> Backported from mainline 2019-07-16 Jeff Law <l...@redhat.com> PR rtl-optimization/91173 * tree-ssa-address.c (addr_for_mem_ref): If the base is an SSA_NAME with a constant value, fold its value into the offset and clear the base before calling gen_addr_rtx. * g++.dg/pr91173.C: New test. diff --git gcc/testsuite/g++.dg/pr91173.C gcc/testsuite/g++.dg/pr91173.C new file mode 100644 index 00000000000..b8fb41ba0cd --- /dev/null +++ gcc/testsuite/g++.dg/pr91173.C @@ -0,0 +1,45 @@ +class a { + int b; + void *c; + +public: + bool aa(); + int &ab() { + if (aa()) { + void *d(c); + return static_cast<int *>(d)[b]; + } + return *(int *)0; + } +}; +typedef enum {E} e; +class f : public a { + int g; + +public: + int ac() { + if (g) + return 1; + return ac(); + } +}; +int *ad; +struct h { + static int ae(e, int *m) { + f ag; + int *ah; + while (!0) { + ad = &ag.ab(); + ah = ad + ag.ac(); + while (ad < ah) + *m = *ad++; + } + } +}; +template <class, class> +void i(int *, int *, int, int *, e n, int *o) { + h::ae(n, o); +} +int aq, ar, as, at, au; +void aw() { i<int, bool>(&aq, &ar, as, &at, (e)0, &au); } + diff --git gcc/tree-ssa-address.c gcc/tree-ssa-address.c index 1c17e935914..2e5d87734d6 100644 --- gcc/tree-ssa-address.c +++ gcc/tree-ssa-address.c @@ -259,6 +259,20 @@ addr_for_mem_ref (struct mem_address *addr, addr_space_t as, ? expand_expr (addr->index, NULL_RTX, pointer_mode, EXPAND_NORMAL) : NULL_RTX); + /* addr->base could be an SSA_NAME that was set to a constant value. The + call to expand_expr may expose that constant. If so, fold the value + into OFF and clear BSE. Otherwise we may later try to pull a mode from + BSE to generate a REG, which won't work with constants because they + are modeless. */ + if (bse && GET_CODE (bse) == CONST_INT) + { + if (off) + off = simplify_gen_binary (PLUS, pointer_mode, bse, off); + else + off = bse; + gcc_assert (GET_CODE (off) == CONST_INT); + bse = NULL_RTX; + } gen_addr_rtx (pointer_mode, sym, bse, idx, st, off, &address, NULL, NULL); if (pointer_mode != address_mode) address = convert_memory_address (address_mode, address);