From 8b8f3117263ca79b3febadadb07732588d99d5f6 Mon Sep 17 00:00:00 2001 From: Alex Coplan Date: Mon, 18 May 2020 16:29:04 +0100 Subject: [PATCH] [arm] Don't generate invalid LDRD insns This fixes a bug in the arm backend where GCC generates invalid LDRD instructions. The LDRD instruction requires the first transfer register to be even, but GCC attempts to use odd registers here. For example, with the following C code: struct c { double a; } __attribute((aligned)) __attribute((packed)); struct c d; struct c f(struct c); void e() { f(d); } The struct d is passed in registers r1 and r2 to the function f, and GCC attempted to do this with a LDRD instruction when compiling with -march=armv7-a on a soft float toolchain. The fix is analogous to the corresponding one for STRD in the same function: https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=52057dc4ac5295caebf83147f688d769c93cbc8d 2020-05-18 Alex Coplan gcc/: * config/arm/arm.c (output_move_double): Fix codegen when loading into a register pair with an odd base register. gcc/testsuite/: * gcc.c-torture/compile/packed-aligned-1.c: New test. * gcc.c-torture/execute/packed-aligned.c: New test. --- gcc/ChangeLog | 5 ++++ gcc/config/arm/arm.c | 28 +++++++++++-------- gcc/testsuite/ChangeLog | 4 +++ .../gcc.c-torture/compile/packed-aligned-1.c | 11 ++++++++ .../gcc.c-torture/execute/packed-aligned.c | 28 +++++++++++++++++++ 5 files changed, 64 insertions(+), 12 deletions(-) create mode 100644 gcc/testsuite/gcc.c-torture/compile/packed-aligned-1.c create mode 100644 gcc/testsuite/gcc.c-torture/execute/packed-aligned.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 580b3cda64c..dffe88fdcca 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2020-05-18 Alex Coplan + + * config/arm/arm.c (output_move_double): Fix codegen when loading into + a register pair with an odd base register. + 2020-05-18 Uroš Bizjak * config/i386/i386-expand.c (ix86_expand_fp_absneg_operator): diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c index 349918a9bfa..635e7adac45 100644 --- a/gcc/config/arm/arm.c +++ b/gcc/config/arm/arm.c @@ -19575,6 +19575,7 @@ output_move_double (rtx *operands, bool emit, int *count) if (code0 == REG) { unsigned int reg0 = REGNO (operands[0]); + const bool can_ldrd = TARGET_LDRD && (TARGET_THUMB2 || (reg0 % 2 == 0)); otherops[0] = gen_rtx_REG (SImode, 1 + reg0); @@ -19586,7 +19587,7 @@ output_move_double (rtx *operands, bool emit, int *count) if (emit) { - if (TARGET_LDRD + if (can_ldrd && !(fix_cm3_ldrd && reg0 == REGNO(XEXP (operands[1], 0)))) output_asm_insn ("ldrd%?\t%0, [%m1]", operands); else @@ -19595,7 +19596,7 @@ output_move_double (rtx *operands, bool emit, int *count) break; case PRE_INC: - gcc_assert (TARGET_LDRD); + gcc_assert (can_ldrd); if (emit) output_asm_insn ("ldrd%?\t%0, [%m1, #8]!", operands); break; @@ -19603,7 +19604,7 @@ output_move_double (rtx *operands, bool emit, int *count) case PRE_DEC: if (emit) { - if (TARGET_LDRD) + if (can_ldrd) output_asm_insn ("ldrd%?\t%0, [%m1, #-8]!", operands); else output_asm_insn ("ldmdb%?\t%m1!, %M0", operands); @@ -19613,7 +19614,7 @@ output_move_double (rtx *operands, bool emit, int *count) case POST_INC: if (emit) { - if (TARGET_LDRD) + if (can_ldrd) output_asm_insn ("ldrd%?\t%0, [%m1], #8", operands); else output_asm_insn ("ldmia%?\t%m1!, %M0", operands); @@ -19621,7 +19622,7 @@ output_move_double (rtx *operands, bool emit, int *count) break; case POST_DEC: - gcc_assert (TARGET_LDRD); + gcc_assert (can_ldrd); if (emit) output_asm_insn ("ldrd%?\t%0, [%m1], #-8", operands); break; @@ -19643,6 +19644,7 @@ output_move_double (rtx *operands, bool emit, int *count) /* Registers overlap so split out the increment. */ if (emit) { + gcc_assert (can_ldrd); output_asm_insn ("add%?\t%1, %1, %2", otherops); output_asm_insn ("ldrd%?\t%0, [%1] @split", otherops); } @@ -19654,10 +19656,11 @@ output_move_double (rtx *operands, bool emit, int *count) /* Use a single insn if we can. FIXME: IWMMXT allows offsets larger than ldrd can handle, fix these up with a pair of ldr. */ - if (TARGET_THUMB2 + if (can_ldrd + && (TARGET_THUMB2 || !CONST_INT_P (otherops[2]) || (INTVAL (otherops[2]) > -256 - && INTVAL (otherops[2]) < 256)) + && INTVAL (otherops[2]) < 256))) { if (emit) output_asm_insn ("ldrd%?\t%0, [%1, %2]!", otherops); @@ -19680,10 +19683,11 @@ output_move_double (rtx *operands, bool emit, int *count) /* Use a single insn if we can. FIXME: IWMMXT allows offsets larger than ldrd can handle, fix these up with a pair of ldr. */ - if (TARGET_THUMB2 + if (can_ldrd + && (TARGET_THUMB2 || !CONST_INT_P (otherops[2]) || (INTVAL (otherops[2]) > -256 - && INTVAL (otherops[2]) < 256)) + && INTVAL (otherops[2]) < 256))) { if (emit) output_asm_insn ("ldrd%?\t%0, [%1], %2", otherops); @@ -19714,7 +19718,7 @@ output_move_double (rtx *operands, bool emit, int *count) operands[1] = otherops[0]; if (emit) { - if (TARGET_LDRD) + if (can_ldrd) output_asm_insn ("ldrd%?\t%0, [%1]", operands); else output_asm_insn ("ldmia%?\t%1, %M0", operands); @@ -19759,7 +19763,7 @@ output_move_double (rtx *operands, bool emit, int *count) } otherops[0] = gen_rtx_REG(SImode, REGNO(operands[0]) + 1); operands[1] = otherops[0]; - if (TARGET_LDRD + if (can_ldrd && (REG_P (otherops[2]) || TARGET_THUMB2 || (CONST_INT_P (otherops[2]) @@ -19820,7 +19824,7 @@ output_move_double (rtx *operands, bool emit, int *count) if (count) *count = 2; - if (TARGET_LDRD) + if (can_ldrd) return "ldrd%?\t%0, [%1]"; return "ldmia%?\t%1, %M0"; diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 33425f259b4..89423f5dfb9 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2020-05-18 Alex Coplan + * gcc.c-torture/compile/packed-aligned-1.c: New test. + * gcc.c-torture/execute/packed-aligned.c: New test. + 2020-05-18 Richard Biener PR middle-end/95171 diff --git a/gcc/testsuite/gcc.c-torture/compile/packed-aligned-1.c b/gcc/testsuite/gcc.c-torture/compile/packed-aligned-1.c new file mode 100644 index 00000000000..9f0923e29ee --- /dev/null +++ b/gcc/testsuite/gcc.c-torture/compile/packed-aligned-1.c @@ -0,0 +1,11 @@ +struct c { + double a; +} __attribute((packed)) __attribute((aligned)); + +void f(struct c *, struct c); + +void g(struct c *ptr) +{ + ptr++; + f(ptr, *ptr); +} diff --git a/gcc/testsuite/gcc.c-torture/execute/packed-aligned.c b/gcc/testsuite/gcc.c-torture/execute/packed-aligned.c new file mode 100644 index 00000000000..f768af0ab02 --- /dev/null +++ b/gcc/testsuite/gcc.c-torture/execute/packed-aligned.c @@ -0,0 +1,28 @@ +struct c { + double a; +} __attribute((packed)) __attribute((aligned)); + +extern void abort(void); + +double g_expect = 32.25; + +void f(unsigned x, struct c y) +{ + if (x != 0) + abort(); + + if (y.a != g_expect) + abort(); +} + +struct c e = { 64.25 }; + +int main(void) +{ + struct c d = { 32.25 }; + f(0, d); + + g_expect = 64.25; + f(0, e); + return 0; +} -- 2.30.2