On Tue, Jan 2, 2024 at 2:37 PM <pan2...@intel.com> wrote: > > From: Pan Li <pan2...@intel.com> > > According to the sematics of no-signed-zeros option, the backend > like RISC-V should treat the minus zero -0.0f as plus zero 0.0f. > > Consider below example with option -fno-signed-zeros. > > void > test (float *a) > { > *a = -0.0; > } > > We will generate code as below, which doesn't treat the minus zero > as plus zero. > > test: > lui a5,%hi(.LC0) > flw fa5,%lo(.LC0)(a5) > fsw fa5,0(a0) > ret > > .LC0: > .word -2147483648 // aka -0.0 (0x80000000 in hex) > > This patch would like to fix the bug and treat the minus zero -0.0 > as plus zero, aka +0.0. Thus after this patch we will have asm code > as below for the above sampe code. > > test: > sw zero,0(a0) > ret > > This patch also fix the run failure of the test case pr30957-1.c. The > below tests are passed for this patch.
We don't really expect targets to do this. The small testcase above is somewhat ill-formed with -fno-signed-zeros. Note there's no -0.0 in pr30957-1.c so why does that one fail for you? Does the -fvariable-expansion-in-unroller code maybe not trigger for riscv? I think we should go to PR30957 and see what that was filed originally for, the testcase doesn't make much sense to me. > * The riscv regression tests. > * The pr30957-1.c run tests. > > gcc/ChangeLog: > > * config/riscv/constraints.md: Leverage func > riscv_float_const_zero_rtx_p > for predicating the rtx is const zero float or not. > * config/riscv/predicates.md: Ditto. > * config/riscv/riscv.cc (riscv_const_insns): Ditto. > (riscv_float_const_zero_rtx_p): New func impl for predicating the rtx > is > const zero float or not. > (riscv_const_zero_rtx_p): New func impl for predicating the rtx > is const zero (both int and fp) or not. > * config/riscv/riscv-protos.h (riscv_float_const_zero_rtx_p): > New func decl. > (riscv_const_zero_rtx_p): Ditto. > * config/riscv/riscv.md: Making sure the operand[1] of movfp is > CONST0_RTX when the operand[1] is const zero float. > > gcc/testsuite/ChangeLog: > > * gcc.target/riscv/no-signed-zeros-0.c: New test. > * gcc.target/riscv/no-signed-zeros-1.c: New test. > * gcc.target/riscv/no-signed-zeros-2.c: New test. > * gcc.target/riscv/no-signed-zeros-3.c: New test. > * gcc.target/riscv/no-signed-zeros-4.c: New test. > * gcc.target/riscv/no-signed-zeros-5.c: New test. > * gcc.target/riscv/no-signed-zeros-run-0.c: New test. > * gcc.target/riscv/no-signed-zeros-run-1.c: New test. > > Signed-off-by: Pan Li <pan2...@intel.com> > --- > gcc/config/riscv/constraints.md | 2 +- > gcc/config/riscv/predicates.md | 2 +- > gcc/config/riscv/riscv-protos.h | 2 + > gcc/config/riscv/riscv.cc | 35 ++++++++++++- > gcc/config/riscv/riscv.md | 49 ++++++++++++++++--- > .../gcc.target/riscv/no-signed-zeros-0.c | 26 ++++++++++ > .../gcc.target/riscv/no-signed-zeros-1.c | 28 +++++++++++ > .../gcc.target/riscv/no-signed-zeros-2.c | 26 ++++++++++ > .../gcc.target/riscv/no-signed-zeros-3.c | 28 +++++++++++ > .../gcc.target/riscv/no-signed-zeros-4.c | 26 ++++++++++ > .../gcc.target/riscv/no-signed-zeros-5.c | 28 +++++++++++ > .../gcc.target/riscv/no-signed-zeros-run-0.c | 36 ++++++++++++++ > .../gcc.target/riscv/no-signed-zeros-run-1.c | 36 ++++++++++++++ > 13 files changed, 314 insertions(+), 10 deletions(-) > create mode 100644 gcc/testsuite/gcc.target/riscv/no-signed-zeros-0.c > create mode 100644 gcc/testsuite/gcc.target/riscv/no-signed-zeros-1.c > create mode 100644 gcc/testsuite/gcc.target/riscv/no-signed-zeros-2.c > create mode 100644 gcc/testsuite/gcc.target/riscv/no-signed-zeros-3.c > create mode 100644 gcc/testsuite/gcc.target/riscv/no-signed-zeros-4.c > create mode 100644 gcc/testsuite/gcc.target/riscv/no-signed-zeros-5.c > create mode 100644 gcc/testsuite/gcc.target/riscv/no-signed-zeros-run-0.c > create mode 100644 gcc/testsuite/gcc.target/riscv/no-signed-zeros-run-1.c > > diff --git a/gcc/config/riscv/constraints.md b/gcc/config/riscv/constraints.md > index de4359af00d..db1d5e1385f 100644 > --- a/gcc/config/riscv/constraints.md > +++ b/gcc/config/riscv/constraints.md > @@ -108,7 +108,7 @@ (define_constraint "DnS" > (define_constraint "G" > "@internal" > (and (match_code "const_double") > - (match_test "op == CONST0_RTX (mode)"))) > + (match_test "riscv_float_const_zero_rtx_p (op)"))) > > (define_memory_constraint "A" > "An address that is held in a general-purpose register." > diff --git a/gcc/config/riscv/predicates.md b/gcc/config/riscv/predicates.md > index b87a6900841..b428d842101 100644 > --- a/gcc/config/riscv/predicates.md > +++ b/gcc/config/riscv/predicates.md > @@ -78,7 +78,7 @@ (define_predicate "sleu_operand" > > (define_predicate "const_0_operand" > (and (match_code "const_int,const_wide_int,const_double,const_vector") > - (match_test "op == CONST0_RTX (GET_MODE (op))"))) > + (match_test "riscv_const_zero_rtx_p (op)"))) > > (define_predicate "const_1_operand" > (and (match_code "const_int,const_wide_int,const_vector") > diff --git a/gcc/config/riscv/riscv-protos.h b/gcc/config/riscv/riscv-protos.h > index 31049ef7523..fcf30e084a3 100644 > --- a/gcc/config/riscv/riscv-protos.h > +++ b/gcc/config/riscv/riscv-protos.h > @@ -131,6 +131,8 @@ extern void riscv_asm_output_external (FILE *, const > tree, const char *); > extern bool > riscv_zcmp_valid_stack_adj_bytes_p (HOST_WIDE_INT, int); > extern void riscv_legitimize_poly_move (machine_mode, rtx, rtx, rtx); > +extern bool riscv_float_const_zero_rtx_p (rtx); > +extern bool riscv_const_zero_rtx_p (rtx); > > #ifdef RTX_CODE > extern void riscv_expand_int_scc (rtx, enum rtx_code, rtx, rtx, bool > *invert_ptr = 0); > diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc > index 0d1cbc5cb5f..a8ad86b7068 100644 > --- a/gcc/config/riscv/riscv.cc > +++ b/gcc/config/riscv/riscv.cc > @@ -1635,7 +1635,7 @@ riscv_const_insns (rtx x) > return 1; > > /* We can use x0 to load floating-point zero. */ > - return x == CONST0_RTX (GET_MODE (x)) ? 1 : 0; > + return riscv_float_const_zero_rtx_p (x) ? 1 : 0; > case CONST_VECTOR: > { > /* TODO: This is not accurate, we will need to > @@ -9481,6 +9481,39 @@ riscv_zcmp_valid_stack_adj_bytes_p (HOST_WIDE_INT > total, int regs_num) > || additioanl_bytes == ZCMP_MAX_SPIMM * ZCMP_SP_INC_STEP; > } > > +/* Return true if rtx op is const zero of the floating-point. */ > +bool > +riscv_float_const_zero_rtx_p (rtx op) > +{ > + machine_mode mode = GET_MODE (op); > + > + if (GET_MODE_CLASS (mode) != MODE_FLOAT) > + return false; > + > + if (GET_CODE (op) != CONST_DOUBLE) > + return false; > + > + const struct real_value *op_rvalue = CONST_DOUBLE_REAL_VALUE (op); > + > + if (REAL_VALUE_MINUS_ZERO (*op_rvalue)) > + return !HONOR_SIGNED_ZEROS (mode); > + > + return real_equal (op_rvalue, &dconst0); > +} > + > +/* Return true if rtx op is const zero, include both the integer > + and floating-point. */ > +bool > +riscv_const_zero_rtx_p (rtx op) > +{ > + machine_mode mode = GET_MODE (op); > + > + if (GET_MODE_CLASS (mode) == MODE_FLOAT) > + return riscv_float_const_zero_rtx_p (op); > + > + return op == CONST0_RTX (mode); > +} > + > /* Return true if it's valid gpr_save pattern. */ > > bool > diff --git a/gcc/config/riscv/riscv.md b/gcc/config/riscv/riscv.md > index 68f7203b676..cd429f6dcdd 100644 > --- a/gcc/config/riscv/riscv.md > +++ b/gcc/config/riscv/riscv.md > @@ -1878,7 +1878,12 @@ (define_insn "*movhf_hardfloat" > "TARGET_ZFHMIN > && (register_operand (operands[0], HFmode) > || reg_or_0_operand (operands[1], HFmode))" > - { return riscv_output_move (operands[0], operands[1]); } > + { > + if (riscv_float_const_zero_rtx_p (operands[1])) > + operands[1] = CONST0_RTX (GET_MODE (operands[1])); > + > + return riscv_output_move (operands[0], operands[1]); > + } > [(set_attr "move_type" > "fmove,fmove,mtc,fpload,fpstore,store,mtc,mfc,move,load,store") > (set_attr "type" "fmove") > (set_attr "mode" "HF")]) > @@ -1889,7 +1894,12 @@ (define_insn "*movhf_softfloat" > "!TARGET_ZFHMIN > && (register_operand (operands[0], HFmode) > || reg_or_0_operand (operands[1], HFmode))" > - { return riscv_output_move (operands[0], operands[1]); } > + { > + if (riscv_float_const_zero_rtx_p (operands[1])) > + operands[1] = CONST0_RTX (GET_MODE (operands[1])); > + > + return riscv_output_move (operands[0], operands[1]); > + } > [(set_attr "move_type" "fmove,move,load,store,mtc,mfc") > (set_attr "type" "fmove") > (set_attr "mode" "HF")]) > @@ -2243,7 +2253,12 @@ (define_insn "*movsf_hardfloat" > "TARGET_HARD_FLOAT > && (register_operand (operands[0], SFmode) > || reg_or_0_operand (operands[1], SFmode))" > - { return riscv_output_move (operands[0], operands[1]); } > + { > + if (riscv_float_const_zero_rtx_p (operands[1])) > + operands[1] = CONST0_RTX (GET_MODE (operands[1])); > + > + return riscv_output_move (operands[0], operands[1]); > + } > [(set_attr "move_type" > "fmove,fmove,mtc,fpload,fpstore,store,mtc,mfc,move,load,store") > (set_attr "type" "fmove") > (set_attr "mode" "SF")]) > @@ -2254,7 +2269,12 @@ (define_insn "*movsf_softfloat" > "!TARGET_HARD_FLOAT > && (register_operand (operands[0], SFmode) > || reg_or_0_operand (operands[1], SFmode))" > - { return riscv_output_move (operands[0], operands[1]); } > + { > + if (riscv_float_const_zero_rtx_p (operands[1])) > + operands[1] = CONST0_RTX (GET_MODE (operands[1])); > + > + return riscv_output_move (operands[0], operands[1]); > + } > [(set_attr "move_type" "move,load,store") > (set_attr "type" "fmove") > (set_attr "mode" "SF")]) > @@ -2279,7 +2299,12 @@ (define_insn "*movdf_hardfloat_rv32" > "!TARGET_64BIT && TARGET_DOUBLE_FLOAT > && (register_operand (operands[0], DFmode) > || reg_or_0_operand (operands[1], DFmode))" > - { return riscv_output_move (operands[0], operands[1]); } > + { > + if (riscv_float_const_zero_rtx_p (operands[1])) > + operands[1] = CONST0_RTX (GET_MODE (operands[1])); > + > + return riscv_output_move (operands[0], operands[1]); > + } > [(set_attr "move_type" > "fmove,fmove,mtc,fpload,fpstore,store,mtc,mfc,move,load,store") > (set_attr "type" "fmove") > (set_attr "mode" "DF")]) > @@ -2290,7 +2315,12 @@ (define_insn "*movdf_hardfloat_rv64" > "TARGET_64BIT && TARGET_DOUBLE_FLOAT > && (register_operand (operands[0], DFmode) > || reg_or_0_operand (operands[1], DFmode))" > - { return riscv_output_move (operands[0], operands[1]); } > + { > + if (riscv_float_const_zero_rtx_p (operands[1])) > + operands[1] = CONST0_RTX (GET_MODE (operands[1])); > + > + return riscv_output_move (operands[0], operands[1]); > + } > [(set_attr "move_type" > "fmove,fmove,mtc,fpload,fpstore,store,mtc,mfc,move,load,store") > (set_attr "type" "fmove") > (set_attr "mode" "DF")]) > @@ -2301,7 +2331,12 @@ (define_insn "*movdf_softfloat" > "!TARGET_DOUBLE_FLOAT > && (register_operand (operands[0], DFmode) > || reg_or_0_operand (operands[1], DFmode))" > - { return riscv_output_move (operands[0], operands[1]); } > + { > + if (riscv_float_const_zero_rtx_p (operands[1])) > + operands[1] = CONST0_RTX (GET_MODE (operands[1])); > + > + return riscv_output_move (operands[0], operands[1]); > + } > [(set_attr "move_type" "move,load,store") > (set_attr "type" "fmove") > (set_attr "mode" "DF")]) > diff --git a/gcc/testsuite/gcc.target/riscv/no-signed-zeros-0.c > b/gcc/testsuite/gcc.target/riscv/no-signed-zeros-0.c > new file mode 100644 > index 00000000000..1eda13a3406 > --- /dev/null > +++ b/gcc/testsuite/gcc.target/riscv/no-signed-zeros-0.c > @@ -0,0 +1,26 @@ > +/* { dg-do compile } */ > +/* { dg-options "-march=rv64gcv -mabi=lp64d -O3 -fno-signed-zeros > -fno-schedule-insns -fno-schedule-insns2" } */ > +/* { dg-skip-if "" { *-*-* } { "-flto" } } */ > +/* { dg-final { check-function-bodies "**" "" } } */ > + > +/* > +** test_float_plus_zero_assign: > +** sw\s+zero,0\([atx][0-9]+\) > +** ret > +*/ > +void > +test_float_plus_zero_assign (float *a) > +{ > + *a = +0.0; > +} > + > +/* > +** test_float_plus_zero_assign: > +** sw\s+zero,0\([atx][0-9]+\) > +** ret > +*/ > +void > +test_float_minus_zero_assign (float *a) > +{ > + *a = -0.0; > +} > diff --git a/gcc/testsuite/gcc.target/riscv/no-signed-zeros-1.c > b/gcc/testsuite/gcc.target/riscv/no-signed-zeros-1.c > new file mode 100644 > index 00000000000..8041ec3ea95 > --- /dev/null > +++ b/gcc/testsuite/gcc.target/riscv/no-signed-zeros-1.c > @@ -0,0 +1,28 @@ > +/* { dg-do compile } */ > +/* { dg-options "-march=rv64gcv -mabi=lp64d -O3 -fno-signed-zeros > -fno-schedule-insns -fno-schedule-insns2" } */ > +/* { dg-skip-if "" { *-*-* } { "-flto" } } */ > +/* { dg-final { check-function-bodies "**" "" } } */ > + > +extern void float_assign (float *a, float b); > + > +/* > +** test_float_plus_zero_assign: > +** fmv\.s\.x\s+fa[0-9]+,\s*zero > +** tail\s+float_assign > +*/ > +void > +test_float_plus_zero_assign (float *a) > +{ > + float_assign (a, +0.0); > +} > + > +/* > +** test_float_minus_zero_assign: > +** fmv\.s\.x\s+fa[0-9]+,\s*zero > +** tail\s+float_assign > +*/ > +void > +test_float_minus_zero_assign (float *a) > +{ > + float_assign (a, -0.0); > +} > diff --git a/gcc/testsuite/gcc.target/riscv/no-signed-zeros-2.c > b/gcc/testsuite/gcc.target/riscv/no-signed-zeros-2.c > new file mode 100644 > index 00000000000..a6996dae4de > --- /dev/null > +++ b/gcc/testsuite/gcc.target/riscv/no-signed-zeros-2.c > @@ -0,0 +1,26 @@ > +/* { dg-do compile } */ > +/* { dg-options "-march=rv64gcv -mabi=lp64d -O3 -fno-signed-zeros > -fno-schedule-insns -fno-schedule-insns2" } */ > +/* { dg-skip-if "" { *-*-* } { "-flto" } } */ > +/* { dg-final { check-function-bodies "**" "" } } */ > + > +/* > +** test_float_plus_zero_assign: > +** sd\s+zero,0\([atx][0-9]+\) > +** ret > +*/ > +void > +test_float_plus_zero_assign (double *a) > +{ > + *a = +0.0; > +} > + > +/* > +** test_float_plus_zero_assign: > +** sd\s+zero,0\([atx][0-9]+\) > +** ret > +*/ > +void > +test_float_minus_zero_assign (double *a) > +{ > + *a = -0.0; > +} > diff --git a/gcc/testsuite/gcc.target/riscv/no-signed-zeros-3.c > b/gcc/testsuite/gcc.target/riscv/no-signed-zeros-3.c > new file mode 100644 > index 00000000000..b4ba8a247df > --- /dev/null > +++ b/gcc/testsuite/gcc.target/riscv/no-signed-zeros-3.c > @@ -0,0 +1,28 @@ > +/* { dg-do compile } */ > +/* { dg-options "-march=rv64gcv -mabi=lp64d -O3 -fno-signed-zeros > -fno-schedule-insns -fno-schedule-insns2" } */ > +/* { dg-skip-if "" { *-*-* } { "-flto" } } */ > +/* { dg-final { check-function-bodies "**" "" } } */ > + > +extern void float_assign (double *a, double b); > + > +/* > +** test_float_plus_zero_assign: > +** fmv\.d\.x\s+fa[0-9]+,\s*zero > +** tail\s+float_assign > +*/ > +void > +test_float_plus_zero_assign (double *a) > +{ > + float_assign (a, +0.0); > +} > + > +/* > +** test_float_minus_zero_assign: > +** fmv\.d\.x\s+fa[0-9]+,\s*zero > +** tail\s+float_assign > +*/ > +void > +test_float_minus_zero_assign (double *a) > +{ > + float_assign (a, -0.0); > +} > diff --git a/gcc/testsuite/gcc.target/riscv/no-signed-zeros-4.c > b/gcc/testsuite/gcc.target/riscv/no-signed-zeros-4.c > new file mode 100644 > index 00000000000..60acf7155d3 > --- /dev/null > +++ b/gcc/testsuite/gcc.target/riscv/no-signed-zeros-4.c > @@ -0,0 +1,26 @@ > +/* { dg-do compile } */ > +/* { dg-options "-march=rv64gcv_zfh -mabi=lp64d -O3 -fno-signed-zeros > -fno-schedule-insns -fno-schedule-insns2" } */ > +/* { dg-skip-if "" { *-*-* } { "-flto" } } */ > +/* { dg-final { check-function-bodies "**" "" } } */ > + > +/* > +** test_float_plus_zero_assign: > +** sh\s+zero,0\([atx][0-9]+\) > +** ret > +*/ > +void > +test_float_plus_zero_assign (_Float16 *a) > +{ > + *a = +0.0; > +} > + > +/* > +** test_float_plus_zero_assign: > +** sh\s+zero,0\([atx][0-9]+\) > +** ret > +*/ > +void > +test_float_minus_zero_assign (_Float16 *a) > +{ > + *a = -0.0; > +} > diff --git a/gcc/testsuite/gcc.target/riscv/no-signed-zeros-5.c > b/gcc/testsuite/gcc.target/riscv/no-signed-zeros-5.c > new file mode 100644 > index 00000000000..d10efbeb37b > --- /dev/null > +++ b/gcc/testsuite/gcc.target/riscv/no-signed-zeros-5.c > @@ -0,0 +1,28 @@ > +/* { dg-do compile } */ > +/* { dg-options "-march=rv64gcv_zfh -mabi=lp64d -O3 -fno-signed-zeros > -fno-schedule-insns -fno-schedule-insns2" } */ > +/* { dg-skip-if "" { *-*-* } { "-flto" } } */ > +/* { dg-final { check-function-bodies "**" "" } } */ > + > +extern void float_assign (_Float16 *a, _Float16 b); > + > +/* > +** test_float_plus_zero_assign: > +** fmv\.h\.x\s+fa[0-9]+,\s*zero > +** tail\s+float_assign > +*/ > +void > +test_float_plus_zero_assign (_Float16 *a) > +{ > + float_assign (a, +0.0); > +} > + > +/* > +** test_float_minus_zero_assign: > +** fmv\.h\.x\s+fa[0-9]+,\s*zero > +** tail\s+float_assign > +*/ > +void > +test_float_minus_zero_assign (_Float16 *a) > +{ > + float_assign (a, -0.0); > +} > diff --git a/gcc/testsuite/gcc.target/riscv/no-signed-zeros-run-0.c > b/gcc/testsuite/gcc.target/riscv/no-signed-zeros-run-0.c > new file mode 100644 > index 00000000000..347e4b0ff74 > --- /dev/null > +++ b/gcc/testsuite/gcc.target/riscv/no-signed-zeros-run-0.c > @@ -0,0 +1,36 @@ > +/* { dg-do run { target { riscv_v } } } */ > +/* { dg-additional-options "-std=c99 -O3 -fno-signed-zeros" } */ > + > +float f_val; > + > +void > +__attribute__ ((noinline)) > +test_float_plus_zero_assign (float *a) > +{ > + *a = +0.0; > +} > + > +void > +__attribute__ ((noinline)) > +test_float_minus_zero_assign (float *a) > +{ > + *a = -0.0; > +} > + > +int > +main () > +{ > + f_val = -1.0; > + test_float_plus_zero_assign (&f_val); > + > + if (__builtin_copysignf (1.0, f_val) != 1.0) > + __builtin_abort (); > + > + f_val = -1.0; > + test_float_minus_zero_assign (&f_val); > + > + if (__builtin_copysignf (1.0, f_val) != 1.0) > + __builtin_abort (); > + > + return 0; > +} > diff --git a/gcc/testsuite/gcc.target/riscv/no-signed-zeros-run-1.c > b/gcc/testsuite/gcc.target/riscv/no-signed-zeros-run-1.c > new file mode 100644 > index 00000000000..1eb1edba457 > --- /dev/null > +++ b/gcc/testsuite/gcc.target/riscv/no-signed-zeros-run-1.c > @@ -0,0 +1,36 @@ > +/* { dg-do run { target { riscv_v } } } */ > +/* { dg-additional-options "-std=c99 -O3 -fno-signed-zeros" } */ > + > +double f_val; > + > +void > +__attribute__ ((noinline)) > +test_float_plus_zero_assign (double *a) > +{ > + *a = +0.0; > +} > + > +void > +__attribute__ ((noinline)) > +test_float_minus_zero_assign (double *a) > +{ > + *a = -0.0; > +} > + > +int > +main () > +{ > + f_val = -1.0; > + test_float_plus_zero_assign (&f_val); > + > + if (__builtin_copysignf (1.0, f_val) != 1.0) > + __builtin_abort (); > + > + f_val = -1.0; > + test_float_minus_zero_assign (&f_val); > + > + if (__builtin_copysignf (1.0, f_val) != 1.0) > + __builtin_abort (); > + > + return 0; > +} > -- > 2.34.1 >