https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91109
--- Comment #12 from Christophe Lyon <clyon at gcc dot gnu.org> --- Indeed, although r274163 fixes the problem I reported, it also introduces a regression when compiling the very same testcase but adding -mthumb: FAIL: gcc.c-torture/execute/20040709-1.c -O2 (internal compiler error) FAIL: gcc.c-torture/execute/20040709-1.c -O2 -flto -fno-use-linker-plugin -flto-partition=none (internal compiler error) FAIL: gcc.c-torture/execute/20040709-3.c -O2 (internal compiler error) FAIL: gcc.c-torture/execute/20040709-3.c -O2 -flto -fno-use-linker-plugin -flto-partition=none (internal compiler error) FAIL: gcc.c-torture/execute/20040709-3.c -O3 -g (internal compiler error) My gcc.log says: /gcc/testsuite/gcc.c-torture/execute/20040709-1.c: In function 'retmeD': /gcc/testsuite/gcc.c-torture/execute/20040709-1.c:19:10: note: parameter passing for argument of type 'struct D' changed in GCC 9.1 /gcc/testsuite/gcc.c-torture/execute/20040709-1.c:95:64: note: in expansion of macro 'T' /gcc/testsuite/gcc.c-torture/execute/20040709-1.c: In function 'testI': /gcc/testsuite/gcc.c-torture/execute/20040709-1.c:100:75: error: insn does not satisfy its constraints: /gcc/testsuite/gcc.c-torture/execute/20040709-1.c:55:10: note: in definition of macro 'T' (insn 311 122 309 8 (parallel [ (set (reg:SI 3 r3 [266]) (truncate:SI (lshiftrt:DI (mult:DI (zero_extend:DI (reg:SI 10 r10 [265])) (zero_extend:DI (reg:SI 8 r8 [267]))) (const_int 32 [0x20])))) (clobber (scratch:SI)) ]) "/gcc/testsuite/gcc.c-torture/execute/20040709-1.c":100:73 70 {*umulsi3_highpart_v6} (nil)) during RTL pass: reload /gcc/testsuite/gcc.c-torture/execute/20040709-1.c:100:75: internal compiler error: in extract_constrain_insn, at recog.c:2211 /gcc/testsuite/gcc.c-torture/execute/20040709-1.c:55:10: note: in definition of macro 'T' 0x5a7d5d _fatal_insn(char const*, rtx_def const*, char const*, int, char const*) /gcc/rtl-error.c:108 0x5a7d83 _fatal_insn_not_found(rtx_def const*, char const*, int, char const*) /gcc/rtl-error.c:119 0xb7b85d extract_constrain_insn(rtx_insn*) /gcc/recog.c:2211 0xa629b7 check_rtl /gcc/lra.c:2184 0xa67def lra(_IO_FILE*) /gcc/lra.c:2622 0xa19f49 do_reload /gcc/ira.c:5522 0xa19f49 execute /gcc/ira.c:5706