From: Uros Bizjak Date: Fri, 23 Apr 2021 15:29:29 +0000 (+0200) Subject: i386: Fix atomic FP peepholes [PR100182] X-Git-Tag: basepoints/gcc-13~8222 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d2324a5ab3ff097864ae6828cb1db4dd013c70d1;p=thirdparty%2Fgcc.git i386: Fix atomic FP peepholes [PR100182] 64bit loads to/stores from x87 and SSE registers are atomic also on 32-bit targets, so there is no need for additional atomic moves to a temporary register. Introduced load peephole2 patterns assume that there won't be any additional loads from the load location outside the peepholed sequence and wrongly removed the source location initialization. OTOH, introduced store peephole2 patterns assume there won't be any additional loads from the stored location outside the peepholed sequence and wrongly removed the destination location initialization. Note that we can't use plain x87 FST instruction to initialize destination location because FST converts the value to the double-precision format, changing bits during move. The patch restores removed initializations in load and store patterns. Additionally, plain x87 FST in store peephole2 patterns is prevented by limiting the store operand source to SSE registers. 2021-04-23 Uroš Bizjak gcc/ PR target/100182 * config/i386/sync.md (FILD_ATOMIC/FIST_ATOMIC FP load peephole2): Copy operand 3 to operand 4. Use sse_reg_operand as operand 3 predicate. (FILD_ATOMIC/FIST_ATOMIC FP load peephole2 with mem blockage): Ditto. (LDX_ATOMIC/STX_ATOMIC FP load peephole2): Ditto. (LDX_ATOMIC/LDX_ATOMIC FP load peephole2 with mem blockage): Ditto. (FILD_ATOMIC/FIST_ATOMIC FP store peephole2): Copy operand 1 to operand 0. (FILD_ATOMIC/FIST_ATOMIC FP store peephole2 with mem blockage): Ditto. (LDX_ATOMIC/STX_ATOMIC FP store peephole2): Ditto. (LDX_ATOMIC/LDX_ATOMIC FP store peephole2 with mem blockage): Ditto. gcc/testsuite/ PR target/100182 * gcc.target/i386/pr100182.c: New test. * gcc.target/i386/pr71245-1.c (dg-final): Xfail scan-assembler-not. * gcc.target/i386/pr71245-2.c (dg-final): Ditto. --- diff --git a/gcc/config/i386/sync.md b/gcc/config/i386/sync.md index c7c508c8de86..7913b918796a 100644 --- a/gcc/config/i386/sync.md +++ b/gcc/config/i386/sync.md @@ -226,12 +226,13 @@ (set (match_operand:DI 2 "memory_operand") (unspec:DI [(match_dup 0)] UNSPEC_FIST_ATOMIC)) - (set (match_operand:DF 3 "any_fp_register_operand") + (set (match_operand:DF 3 "sse_reg_operand") (match_operand:DF 4 "memory_operand"))] "!TARGET_64BIT && peep2_reg_dead_p (2, operands[0]) && rtx_equal_p (XEXP (operands[4], 0), XEXP (operands[2], 0))" - [(set (match_dup 3) (match_dup 5))] + [(set (match_dup 3) (match_dup 5)) + (set (match_dup 4) (match_dup 3))] "operands[5] = gen_lowpart (DFmode, operands[1]);") (define_peephole2 @@ -243,7 +244,7 @@ UNSPEC_FIST_ATOMIC)) (set (mem:BLK (scratch:SI)) (unspec:BLK [(mem:BLK (scratch:SI))] UNSPEC_MEMORY_BLOCKAGE)) - (set (match_operand:DF 3 "any_fp_register_operand") + (set (match_operand:DF 3 "sse_reg_operand") (match_operand:DF 4 "memory_operand"))] "!TARGET_64BIT && peep2_reg_dead_p (2, operands[0]) @@ -251,6 +252,7 @@ [(const_int 0)] { emit_move_insn (operands[3], gen_lowpart (DFmode, operands[1])); + emit_move_insn (operands[4], operands[3]); emit_insn (gen_memory_blockage ()); DONE; }) @@ -262,12 +264,13 @@ (set (match_operand:DI 2 "memory_operand") (unspec:DI [(match_dup 0)] UNSPEC_STX_ATOMIC)) - (set (match_operand:DF 3 "any_fp_register_operand") + (set (match_operand:DF 3 "sse_reg_operand") (match_operand:DF 4 "memory_operand"))] "!TARGET_64BIT && peep2_reg_dead_p (2, operands[0]) && rtx_equal_p (XEXP (operands[4], 0), XEXP (operands[2], 0))" - [(set (match_dup 3) (match_dup 5))] + [(set (match_dup 3) (match_dup 5)) + (set (match_dup 4) (match_dup 3))] "operands[5] = gen_lowpart (DFmode, operands[1]);") (define_peephole2 @@ -279,7 +282,7 @@ UNSPEC_STX_ATOMIC)) (set (mem:BLK (scratch:SI)) (unspec:BLK [(mem:BLK (scratch:SI))] UNSPEC_MEMORY_BLOCKAGE)) - (set (match_operand:DF 3 "any_fp_register_operand") + (set (match_operand:DF 3 "sse_reg_operand") (match_operand:DF 4 "memory_operand"))] "!TARGET_64BIT && peep2_reg_dead_p (2, operands[0]) @@ -287,6 +290,7 @@ [(const_int 0)] { emit_move_insn (operands[3], gen_lowpart (DFmode, operands[1])); + emit_move_insn (operands[4], operands[3]); emit_insn (gen_memory_blockage ()); DONE; }) @@ -392,7 +396,8 @@ "!TARGET_64BIT && peep2_reg_dead_p (3, operands[2]) && rtx_equal_p (XEXP (operands[0], 0), XEXP (operands[3], 0))" - [(set (match_dup 5) (match_dup 1))] + [(set (match_dup 0) (match_dup 1)) + (set (match_dup 5) (match_dup 1))] "operands[5] = gen_lowpart (DFmode, operands[4]);") (define_peephole2 @@ -411,6 +416,7 @@ && rtx_equal_p (XEXP (operands[0], 0), XEXP (operands[3], 0))" [(const_int 0)] { + emit_move_insn (operands[0], operands[1]); emit_insn (gen_memory_blockage ()); emit_move_insn (gen_lowpart (DFmode, operands[4]), operands[1]); DONE; @@ -428,7 +434,8 @@ "!TARGET_64BIT && peep2_reg_dead_p (3, operands[2]) && rtx_equal_p (XEXP (operands[0], 0), XEXP (operands[3], 0))" - [(set (match_dup 5) (match_dup 1))] + [(set (match_dup 0) (match_dup 1)) + (set (match_dup 5) (match_dup 1))] "operands[5] = gen_lowpart (DFmode, operands[4]);") (define_peephole2 @@ -447,6 +454,7 @@ && rtx_equal_p (XEXP (operands[0], 0), XEXP (operands[3], 0))" [(const_int 0)] { + emit_move_insn (operands[0], operands[1]); emit_insn (gen_memory_blockage ()); emit_move_insn (gen_lowpart (DFmode, operands[4]), operands[1]); DONE; diff --git a/gcc/testsuite/gcc.target/i386/pr100182.c b/gcc/testsuite/gcc.target/i386/pr100182.c new file mode 100644 index 000000000000..2f92a04db730 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr100182.c @@ -0,0 +1,30 @@ +/* { dg-do run { target ia32 } } */ +/* { dg-options "-O2 -march=i686" } */ + +struct S { double _M_fp; }; +union U { double d; unsigned long long int l; }; + +void +__attribute__((noipa)) +foo (void) +{ + struct S a0, a1; + union U u; + double d0, d1; + a0._M_fp = 0.0; + a1._M_fp = 1.0; + __atomic_store_8 (&a0._M_fp, __atomic_load_8 (&a1._M_fp, __ATOMIC_SEQ_CST), __ATOMIC_SEQ_CST); + u.l = __atomic_load_8 (&a0._M_fp, __ATOMIC_SEQ_CST); + d0 = u.d; + u.l = __atomic_load_8 (&a1._M_fp, __ATOMIC_SEQ_CST); + d1 = u.d; + if (d0 != d1) + __builtin_abort (); +} + +int +main () +{ + foo (); + return 0; +} diff --git a/gcc/testsuite/gcc.target/i386/pr71245-1.c b/gcc/testsuite/gcc.target/i386/pr71245-1.c index be0b7602a8cf..02c0dcb80b65 100644 --- a/gcc/testsuite/gcc.target/i386/pr71245-1.c +++ b/gcc/testsuite/gcc.target/i386/pr71245-1.c @@ -19,4 +19,4 @@ void foo_d (void) __atomic_store_n (&d.ll, tmp.ll, __ATOMIC_SEQ_CST); } -/* { dg-final { scan-assembler-not "(fistp|fild)" } } */ +/* { dg-final { scan-assembler-not "(fistp|fild)" { xfail *-*-* } } } */ diff --git a/gcc/testsuite/gcc.target/i386/pr71245-2.c b/gcc/testsuite/gcc.target/i386/pr71245-2.c index 65c139849d53..bf37a8cbb713 100644 --- a/gcc/testsuite/gcc.target/i386/pr71245-2.c +++ b/gcc/testsuite/gcc.target/i386/pr71245-2.c @@ -19,4 +19,4 @@ void foo_d (void) __atomic_store_n (&d.ll, tmp.ll, __ATOMIC_SEQ_CST); } -/* { dg-final { scan-assembler-not "movlps" } } */ +/* { dg-final { scan-assembler-not "movlps" { xfail *-*-* } } } */