LGTM, I think long jump is another issue and making ra become a fixed register will escalate to an ABI issue, so that should not be a blocker for this patch.
On Tue, Jul 18, 2023 at 4:10 PM yanzhang.wang--- via Gcc-patches <gcc-patches@gcc.gnu.org> wrote: > > From: Yanzhang Wang <yanzhang.w...@intel.com> > > gcc/ChangeLog: > > * config/riscv/riscv.cc (riscv_save_reg_p): Save ra for leaf > when enabling -mno-omit-leaf-frame-pointer > (riscv_option_override): Override omit-frame-pointer. > (riscv_frame_pointer_required): Save s0 for non-leaf function > (TARGET_FRAME_POINTER_REQUIRED): Override defination > * config/riscv/riscv.opt: Add option support. > > gcc/testsuite/ChangeLog: > > * gcc.target/riscv/omit-frame-pointer-1.c: New test. > * gcc.target/riscv/omit-frame-pointer-2.c: New test. > * gcc.target/riscv/omit-frame-pointer-3.c: New test. > * gcc.target/riscv/omit-frame-pointer-4.c: New test. > * gcc.target/riscv/omit-frame-pointer-test.c: New test. > > Signed-off-by: Yanzhang Wang <yanzhang.w...@intel.com> > --- > gcc/config/riscv/riscv.cc | 34 ++++++++++++++++++- > gcc/config/riscv/riscv.opt | 4 +++ > .../gcc.target/riscv/omit-frame-pointer-1.c | 7 ++++ > .../gcc.target/riscv/omit-frame-pointer-2.c | 7 ++++ > .../gcc.target/riscv/omit-frame-pointer-3.c | 7 ++++ > .../gcc.target/riscv/omit-frame-pointer-4.c | 7 ++++ > .../riscv/omit-frame-pointer-test.c | 13 +++++++ > 7 files changed, 78 insertions(+), 1 deletion(-) > create mode 100644 gcc/testsuite/gcc.target/riscv/omit-frame-pointer-1.c > create mode 100644 gcc/testsuite/gcc.target/riscv/omit-frame-pointer-2.c > create mode 100644 gcc/testsuite/gcc.target/riscv/omit-frame-pointer-3.c > create mode 100644 gcc/testsuite/gcc.target/riscv/omit-frame-pointer-4.c > create mode 100644 gcc/testsuite/gcc.target/riscv/omit-frame-pointer-test.c > > diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc > index 706c18416db..caae6168c29 100644 > --- a/gcc/config/riscv/riscv.cc > +++ b/gcc/config/riscv/riscv.cc > @@ -379,6 +379,10 @@ static const struct riscv_tune_info > riscv_tune_info_table[] = { > #include "riscv-cores.def" > }; > > +/* Global variable to distinguish whether we should save and restore s0/fp > for > + function. */ > +static bool riscv_save_frame_pointer; > + > void riscv_frame_info::reset(void) > { > total_size = 0; > @@ -4948,7 +4952,11 @@ riscv_save_reg_p (unsigned int regno) > if (regno == HARD_FRAME_POINTER_REGNUM && frame_pointer_needed) > return true; > > - if (regno == RETURN_ADDR_REGNUM && crtl->calls_eh_return) > + /* Need not to use ra for leaf when frame pointer is turned off by option > + whatever the omit-leaf-frame's value. */ > + bool keep_leaf_ra = frame_pointer_needed && crtl->is_leaf > + && !TARGET_OMIT_LEAF_FRAME_POINTER; > + if (regno == RETURN_ADDR_REGNUM && (crtl->calls_eh_return || keep_leaf_ra)) > return true; > > /* If this is an interrupt handler, then must save extra registers. */ > @@ -6577,6 +6585,21 @@ riscv_option_override (void) > if (flag_pic) > riscv_cmodel = CM_PIC; > > + /* We need to save the fp with ra for non-leaf functions with no fp and ra > + for leaf functions while no-omit-frame-pointer with > + omit-leaf-frame-pointer. The x_flag_omit_frame_pointer has the first > + priority to determine whether the frame pointer is needed. If we do not > + override it, the fp and ra will be stored for leaf functions, which is > not > + our wanted. */ > + riscv_save_frame_pointer = false; > + if (TARGET_OMIT_LEAF_FRAME_POINTER_P (global_options.x_target_flags)) > + { > + if (!global_options.x_flag_omit_frame_pointer) > + riscv_save_frame_pointer = true; > + > + global_options.x_flag_omit_frame_pointer = 1; > + } > + > /* We get better code with explicit relocs for CM_MEDLOW, but > worse code for the others (for now). Pick the best default. */ > if ((target_flags_explicit & MASK_EXPLICIT_RELOCS) == 0) > @@ -7857,6 +7880,12 @@ riscv_preferred_else_value (unsigned, tree, unsigned > int nops, tree *ops) > return nops == 3 ? ops[2] : ops[0]; > } > > +static bool > +riscv_frame_pointer_required (void) > +{ > + return riscv_save_frame_pointer && !crtl->is_leaf; > +} > + > /* Initialize the GCC target structure. */ > #undef TARGET_ASM_ALIGNED_HI_OP > #define TARGET_ASM_ALIGNED_HI_OP "\t.half\t" > @@ -8161,6 +8190,9 @@ riscv_preferred_else_value (unsigned, tree, unsigned > int nops, tree *ops) > #undef TARGET_PREFERRED_ELSE_VALUE > #define TARGET_PREFERRED_ELSE_VALUE riscv_preferred_else_value > > +#undef TARGET_FRAME_POINTER_REQUIRED > +#define TARGET_FRAME_POINTER_REQUIRED riscv_frame_pointer_required > + > struct gcc_target targetm = TARGET_INITIALIZER; > > #include "gt-riscv.h" > diff --git a/gcc/config/riscv/riscv.opt b/gcc/config/riscv/riscv.opt > index dd062f1c8bd..4dfd8f78ad5 100644 > --- a/gcc/config/riscv/riscv.opt > +++ b/gcc/config/riscv/riscv.opt > @@ -138,6 +138,10 @@ Enable the CSR checking for the ISA-dependent CRS and > the read-only CSR. > The ISA-dependent CSR are only valid when the specific ISA is set. The > read-only CSR can not be written by the CSR instructions. > > +momit-leaf-frame-pointer > +Target Mask(OMIT_LEAF_FRAME_POINTER) Save > +Omit the frame pointer in leaf functions. > + > Mask(64BIT) > > Mask(MUL) > diff --git a/gcc/testsuite/gcc.target/riscv/omit-frame-pointer-1.c > b/gcc/testsuite/gcc.target/riscv/omit-frame-pointer-1.c > new file mode 100644 > index 00000000000..c96123ea702 > --- /dev/null > +++ b/gcc/testsuite/gcc.target/riscv/omit-frame-pointer-1.c > @@ -0,0 +1,7 @@ > +/* { dg-do compile } */ > +/* { dg-options "-march=rv64gc -mabi=lp64 -O2 -fno-omit-frame-pointer > -mno-omit-leaf-frame-pointer -fno-inline" } */ > + > +#include "omit-frame-pointer-test.c" > + > +/* { dg-final { scan-assembler-times "sd\tra,\[0-9\]+\\(sp\\)" 2 } } */ > +/* { dg-final { scan-assembler-times "sd\ts0,\[0-9\]+\\(sp\\)" 2 } } */ > diff --git a/gcc/testsuite/gcc.target/riscv/omit-frame-pointer-2.c > b/gcc/testsuite/gcc.target/riscv/omit-frame-pointer-2.c > new file mode 100644 > index 00000000000..067148c6a58 > --- /dev/null > +++ b/gcc/testsuite/gcc.target/riscv/omit-frame-pointer-2.c > @@ -0,0 +1,7 @@ > +/* { dg-do compile } */ > +/* { dg-options "-march=rv64gc -mabi=lp64 -O2 -fno-omit-frame-pointer > -momit-leaf-frame-pointer -fno-inline" } */ > + > +#include "omit-frame-pointer-test.c" > + > +/* { dg-final { scan-assembler-times "sd\tra,\[0-9\]+\\(sp\\)" 1 } } */ > +/* { dg-final { scan-assembler-times "sd\ts0,\[0-9\]+\\(sp\\)" 1 } } */ > diff --git a/gcc/testsuite/gcc.target/riscv/omit-frame-pointer-3.c > b/gcc/testsuite/gcc.target/riscv/omit-frame-pointer-3.c > new file mode 100644 > index 00000000000..b4d7d6f4f0d > --- /dev/null > +++ b/gcc/testsuite/gcc.target/riscv/omit-frame-pointer-3.c > @@ -0,0 +1,7 @@ > +/* { dg-do compile } */ > +/* { dg-options "-march=rv64gc -mabi=lp64 -O2 -fomit-frame-pointer > -mno-omit-leaf-frame-pointer -fno-inline" } */ > + > +#include "omit-frame-pointer-test.c" > + > +/* { dg-final { scan-assembler-times "sd\tra,\[0-9\]+\\(sp\\)" 1 } } */ > +/* { dg-final { scan-assembler-not "sd\ts0,\[0-9\]+\\(sp\\)"} } */ > diff --git a/gcc/testsuite/gcc.target/riscv/omit-frame-pointer-4.c > b/gcc/testsuite/gcc.target/riscv/omit-frame-pointer-4.c > new file mode 100644 > index 00000000000..5a5b540ef4e > --- /dev/null > +++ b/gcc/testsuite/gcc.target/riscv/omit-frame-pointer-4.c > @@ -0,0 +1,7 @@ > +/* { dg-do compile } */ > +/* { dg-options "-march=rv64gc -mabi=lp64 -O2 -fomit-frame-pointer > -momit-leaf-frame-pointer -fno-inline" } */ > + > +#include "omit-frame-pointer-test.c" > + > +/* { dg-final { scan-assembler-times "sd\tra,\[0-9\]+\\(sp\\)" 1 } } */ > +/* { dg-final { scan-assembler-not "sd\ts0,\[0-9\]+\\(sp\\)"} } */ > diff --git a/gcc/testsuite/gcc.target/riscv/omit-frame-pointer-test.c > b/gcc/testsuite/gcc.target/riscv/omit-frame-pointer-test.c > new file mode 100644 > index 00000000000..cf19f001e29 > --- /dev/null > +++ b/gcc/testsuite/gcc.target/riscv/omit-frame-pointer-test.c > @@ -0,0 +1,13 @@ > +int inc(int n) > +{ > + return n + 1; > +} > + > + > +int bar(void) > +{ > + int n = 100; > + n = inc(n); > + n = inc(n) + 100; > + return n; > +} > -- > 2.40.1 >