While working on enabling DFP for AArch64, I noticed new failures in gcc.dg/compat/struct-layout-1.exp (t028) which were not actually caused by DFP types handling. These tests are generated during 'make check' and enabling DFP made generation different (not sure if new non-DFP tests are generated, or if existing ones are generated differently, the tests in question are huge and difficult to compare).
Anyway, I reduced the problem to what I attach at the end of the new gcc.target/aarch64/aapcs64/va_arg-17.c test and rewrote it in the same scheme as other va_arg* AArch64 tests. This is a tough case mixing bitfields and alignment, where aarch64_gimplify_va_arg_expr did not follow the exact same rule as aarch64_layout_arg. When the va_arg parameter uses only one general register, we do not want to introduce double-word alignment. The fix is thus very small, and this patch adds a new test (va_arg-17.c), which contains the reduced offending testcase from struct-layout-1.exp for reference. 2022-04-25 Christophe Lyon <christophe.l...@arm.com> gcc/ PR target/105549 * config/aarch64/aarch64.cc (aarch64_gimplify_va_arg_expr): Fix alignment of single-register parameters. gcc/testssuite/ PR target/105549 * gcc.target/aarch64/aapcs64/va_arg-17.c: New. --- gcc/config/aarch64/aarch64.cc | 4 +- .../gcc.target/aarch64/aapcs64/va_arg-17.c | 105 ++++++++++++++++++ 2 files changed, 108 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/gcc.target/aarch64/aapcs64/va_arg-17.c diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc index f650abbc4ce..bd855758778 100644 --- a/gcc/config/aarch64/aarch64.cc +++ b/gcc/config/aarch64/aarch64.cc @@ -19667,7 +19667,9 @@ aarch64_gimplify_va_arg_expr (tree valist, tree type, gimple_seq *pre_p, rsize = ROUND_UP (size, UNITS_PER_WORD); nregs = rsize / UNITS_PER_WORD; - if (align > 8) + /* Align on double-word only if we need 2 registers, like in + aarch64_layout_arg. */ + if (align > 8 && nregs == 2) { if (abi_break && warn_psabi) inform (input_location, "parameter passing for argument of type " diff --git a/gcc/testsuite/gcc.target/aarch64/aapcs64/va_arg-17.c b/gcc/testsuite/gcc.target/aarch64/aapcs64/va_arg-17.c new file mode 100644 index 00000000000..24895c3ab48 --- /dev/null +++ b/gcc/testsuite/gcc.target/aarch64/aapcs64/va_arg-17.c @@ -0,0 +1,105 @@ +/* Test AAPCS64 layout and __builtin_va_arg. + + This test covers a corner case where a composite type parameter fits in one + register: we do not need a double-word alignment when accessing it in the + va_arg stack area. */ + +/* { dg-do run { target aarch64*-*-* } } */ + +#ifndef IN_FRAMEWORK +#define AAPCS64_TEST_STDARG +#define TESTFILE "va_arg-17.c" +#include "type-def.h" + +enum E6 { e6_0, e6_1, e6_2, e6_3, e6_65533 = 65533, e6_65534, e6_65535 }; +typedef enum E6 Tal16E6 __attribute__((aligned (16))); +typedef unsigned int Tuint; + +int fails; + +union S2844 { + Tuint a:((((10) - 1) & 31) + 1); + Tal16E6 __attribute__((aligned (2), packed)) b:31; + struct{}c[0]; +} ; +union S2844 s2844; +union S2844 a2844[5]; + +#define HAS_DATA_INIT_FUNC +void init_data () +{ + memset (&s2844, '\0', sizeof (s2844)); + memset (a2844, '\0', sizeof (a2844)); + s2844.a = 799U; + a2844[2].a = 586U; +} + +#include "abitest.h" +#else + ARG (int , 1 , W0 , LAST_NAMED_ARG_ID) + DOTS + ANON_PROMOTED (float , 1.0f, double, 1.0, D0, 1) + ANON (union S2844 , s2844 , X1 , 2) + ANON (long long , 2LL , X2 , 3) + ANON (union S2844 , a2844[2] , X3 , 4) + LAST_ANON (union S2844 , a2844[2] , X4 , 5) +#endif + +#if 0 + /* This test is derived from a case generated by struct-layout-1.exp: */ + +enum E6 { e6_0, e6_1, e6_2, e6_3, e6_65533 = 65533, e6_65534, e6_65535 }; +typedef enum E6 Tal16E6 __attribute__((aligned (16))); +typedef unsigned int Tuint; + +int fails; + +union S2844 { + Tuint a:((((10) - 1) & 31) + 1); + Tal16E6 __attribute__((aligned (2), packed)) b:31; + struct{}c[0]; +} ; +union S2844 s2844; +union S2844 a2844[5]; + +typedef __builtin_va_list __gnuc_va_list; +typedef __gnuc_va_list va_list; + +void check2844va (int z, ...) { + union S2844 arg, *p; + va_list ap; + + __builtin_va_start(ap,z); + if (__builtin_va_arg(ap,double) != 1.0) + printf ("fail %d.%d\n", 2844, 0), ++fails; + + p = &s2844; + arg = __builtin_va_arg(ap,union S2844); /* This would fail. */ + if (p->a != arg.a) + printf ("fail %d.%d\n", 2844, 1), ++fails; + + if (__builtin_va_arg(ap,long long) != 3LL) + printf ("fail %d.%d\n", 2844, 2), ++fails; + + p = &a2844[2]; + arg = __builtin_va_arg(ap,union S2844); /* This would fail. */ + if (p->a != arg.a) + printf ("fail %d.%d\n", 2844, 3), ++fails; + + arg = __builtin_va_arg(ap,union S2844); /* This would fail. */ + if (p->a != arg.a) + printf ("fail %d.%d\n", 2844, 4), ++fails; + + __builtin_va_end(ap); +} + +int main (void) { + int i, j; + memset (&s2844, '\0', sizeof (s2844)); + memset (a2844, '\0', sizeof (a2844)); + s2844.a = 799U; + a2844[2].a = 586U; + check2844va (1, 1.0, s2844, 2LL, a2844[2], a2844[2]); + exit (fails != 0); +} +#endif /* 0 */ -- 2.25.1