Bootstrapped and regtested on mips64el-linux-gnuabi64. I'm not sure if it's "correct" to clobber other registers during the zeroing of scratch registers. But I can't really come up with a better idea: on MIPS there is no simple way to clear one bit in FCSR (i. e. FCC[x]). We can't just use "c.f.s $fccx,$f0,$f0" because it will raise an exception if $f0 contains a sNaN.
-- This fixes the ICEs using -fzero-call-used-regs=all for MIPS target. OpenSSH-8.9p1 has started to enable this by default, giving us a reason to fix -fzero-call-used-regs for more targets. gcc/ PR target/104817 PR target/104820 * config/mips/mips.cc (mips_zero_call_used_regs): New function. (TARGET_ZERO_CALL_USED_REGS): Define. * config/mips/mips.md (mips_zero_fcc): New insn. gcc/testsuite * c-c++-common/zero-scratch-regs-8.c: Enable for MIPS. * c-c++-common/zero-scratch-regs-9.c: Likewise. * c-c++-common/zero-scratch-regs-10.c: Likewise. * c-c++-common/zero-scratch-regs-11.c: Likewise. --- gcc/config/mips/mips.cc | 47 +++++++++++++++++++ gcc/config/mips/mips.md | 6 +++ .../c-c++-common/zero-scratch-regs-10.c | 2 +- .../c-c++-common/zero-scratch-regs-11.c | 2 +- .../c-c++-common/zero-scratch-regs-8.c | 2 +- .../c-c++-common/zero-scratch-regs-9.c | 2 +- 6 files changed, 57 insertions(+), 4 deletions(-) diff --git a/gcc/config/mips/mips.cc b/gcc/config/mips/mips.cc index 4f9683e8bf4..f0d6c8f564c 100644 --- a/gcc/config/mips/mips.cc +++ b/gcc/config/mips/mips.cc @@ -22611,6 +22611,51 @@ mips_asm_file_end (void) if (NEED_INDICATE_EXEC_STACK) file_end_indicate_exec_stack (); } + +static HARD_REG_SET +mips_zero_call_used_regs (HARD_REG_SET need_zeroed_hardregs) +{ + HARD_REG_SET zeroed_hardregs; + CLEAR_HARD_REG_SET (zeroed_hardregs); + + if (TEST_HARD_REG_BIT (need_zeroed_hardregs, HI_REGNUM)) + { + /* Clear HI and LO altogether. MIPS target treats HILO as a + double-word register. */ + machine_mode dword_mode = TARGET_64BIT ? TImode : DImode; + rtx hilo = gen_rtx_REG (dword_mode, MD_REG_FIRST); + rtx zero = CONST0_RTX (dword_mode); + emit_move_insn (hilo, zero); + + SET_HARD_REG_BIT (zeroed_hardregs, HI_REGNUM); + if (TEST_HARD_REG_BIT (need_zeroed_hardregs, LO_REGNUM)) + SET_HARD_REG_BIT (zeroed_hardregs, LO_REGNUM); + else + emit_clobber (gen_rtx_REG (word_mode, LO_REGNUM)); + } + + bool zero_fcc = false; + for (int i = ST_REG_FIRST; i <= ST_REG_LAST; i++) + if (TEST_HARD_REG_BIT (need_zeroed_hardregs, i)) + zero_fcc = true; + + /* MIPS does not have a simple way to clear one bit in FCC. We just + clear FCC with ctc1 and clobber all FCC bits. */ + if (zero_fcc) + { + emit_insn (gen_mips_zero_fcc ()); + for (int i = ST_REG_FIRST; i <= ST_REG_LAST; i++) + if (TEST_HARD_REG_BIT (need_zeroed_hardregs, i)) + SET_HARD_REG_BIT (zeroed_hardregs, i); + else + emit_clobber (gen_rtx_REG (CCmode, i)); + } + + need_zeroed_hardregs &= ~zeroed_hardregs; + return zeroed_hardregs | + default_zero_call_used_regs (need_zeroed_hardregs); +} + /* Initialize the GCC target structure. */ #undef TARGET_ASM_ALIGNED_HI_OP @@ -22919,6 +22964,8 @@ mips_asm_file_end (void) #undef TARGET_ASM_FILE_END #define TARGET_ASM_FILE_END mips_asm_file_end +#undef TARGET_ZERO_CALL_USED_REGS +#define TARGET_ZERO_CALL_USED_REGS mips_zero_call_used_regs struct gcc_target targetm = TARGET_INITIALIZER; diff --git a/gcc/config/mips/mips.md b/gcc/config/mips/mips.md index e0f0a582732..edf58710cdd 100644 --- a/gcc/config/mips/mips.md +++ b/gcc/config/mips/mips.md @@ -96,6 +96,7 @@ (define_c_enum "unspec" [ ;; Floating-point environment. UNSPEC_GET_FCSR UNSPEC_SET_FCSR + UNSPEC_ZERO_FCC ;; HI/LO moves. UNSPEC_MFHI @@ -7670,6 +7671,11 @@ (define_insn "*mips_set_fcsr" "TARGET_HARD_FLOAT" "ctc1\t%0,$31") +(define_insn "mips_zero_fcc" + [(unspec_volatile [(const_int 0)] UNSPEC_ZERO_FCC)] + "TARGET_HARD_FLOAT" + "ctc1\t$0,$25") + ;; See tls_get_tp_mips16_<mode> for why this form is used. (define_insn "mips_set_fcsr_mips16_<mode>" [(unspec_volatile:SI [(match_operand:P 0 "call_insn_operand" "dS") diff --git a/gcc/testsuite/c-c++-common/zero-scratch-regs-10.c b/gcc/testsuite/c-c++-common/zero-scratch-regs-10.c index 96e0b79b328..c23b2ceb391 100644 --- a/gcc/testsuite/c-c++-common/zero-scratch-regs-10.c +++ b/gcc/testsuite/c-c++-common/zero-scratch-regs-10.c @@ -1,5 +1,5 @@ /* { dg-do run } */ -/* { dg-skip-if "not implemented" { ! { i?86*-*-* x86_64*-*-* sparc*-*-* aarch64*-*-* nvptx*-*-* s390*-*-* } } } */ +/* { dg-skip-if "not implemented" { ! { i?86*-*-* x86_64*-*-* sparc*-*-* aarch64*-*-* nvptx*-*-* s390*-*-* mips*-*-* } } } */ /* { dg-options "-O2" } */ #include <assert.h> diff --git a/gcc/testsuite/c-c++-common/zero-scratch-regs-11.c b/gcc/testsuite/c-c++-common/zero-scratch-regs-11.c index 0714f95a04f..f51f5a2161c 100644 --- a/gcc/testsuite/c-c++-common/zero-scratch-regs-11.c +++ b/gcc/testsuite/c-c++-common/zero-scratch-regs-11.c @@ -1,5 +1,5 @@ /* { dg-do run } */ -/* { dg-skip-if "not implemented" { ! { i?86*-*-* x86_64*-*-* sparc*-*-* aarch64*-*-* arm*-*-* nvptx*-*-* s390*-*-* } } } */ +/* { dg-skip-if "not implemented" { ! { i?86*-*-* x86_64*-*-* sparc*-*-* aarch64*-*-* arm*-*-* nvptx*-*-* s390*-*-* mips*-*-* } } } */ /* { dg-options "-O2 -fzero-call-used-regs=all" } */ #include "zero-scratch-regs-10.c" diff --git a/gcc/testsuite/c-c++-common/zero-scratch-regs-8.c b/gcc/testsuite/c-c++-common/zero-scratch-regs-8.c index aceda7e5cb8..3e5e59b3c79 100644 --- a/gcc/testsuite/c-c++-common/zero-scratch-regs-8.c +++ b/gcc/testsuite/c-c++-common/zero-scratch-regs-8.c @@ -1,5 +1,5 @@ /* { dg-do run } */ -/* { dg-skip-if "not implemented" { ! { i?86*-*-* x86_64*-*-* sparc*-*-* aarch64*-*-* arm*-*-* nvptx*-*-* s390*-*-* } } } */ +/* { dg-skip-if "not implemented" { ! { i?86*-*-* x86_64*-*-* sparc*-*-* aarch64*-*-* arm*-*-* nvptx*-*-* s390*-*-* mips*-*-* } } } */ /* { dg-options "-O2 -fzero-call-used-regs=all-arg" } */ #include "zero-scratch-regs-1.c" diff --git a/gcc/testsuite/c-c++-common/zero-scratch-regs-9.c b/gcc/testsuite/c-c++-common/zero-scratch-regs-9.c index f3152a7a732..d88d61accb2 100644 --- a/gcc/testsuite/c-c++-common/zero-scratch-regs-9.c +++ b/gcc/testsuite/c-c++-common/zero-scratch-regs-9.c @@ -1,5 +1,5 @@ /* { dg-do run } */ -/* { dg-skip-if "not implemented" { ! { i?86*-*-* x86_64*-*-* sparc*-*-* aarch64*-*-* arm*-*-* nvptx*-*-* s390*-*-* } } } */ +/* { dg-skip-if "not implemented" { ! { i?86*-*-* x86_64*-*-* sparc*-*-* aarch64*-*-* arm*-*-* nvptx*-*-* s390*-*-* mips*-*-* } } } */ /* { dg-options "-O2 -fzero-call-used-regs=all" } */ #include "zero-scratch-regs-1.c" -- 2.35.1