This makes the float32-basic.c testcase work on sysv (32-bit Linux). "float" is promoted to "double" for varargs. The ABI also only defines the use of double precision in varargs. But _Float32 is not promoted. Since there is no way of passing single-precision float in FPRs we should pass SFmode in GPRs (or memory) instead. This is similar to the 64-bit ABI.
Tested on powerpc64-linux {-m64,-m32}. Committing to trunk. Segher 2018-03-12 Segher Boessenkool <seg...@kernel.crashing.org> * config/rs6000/rs6000.c (abi_v4_pass_in_fpr): Add bool "named" parameter. Use it for SFmode. (rs6000_function_arg_advance_1): Adjust. (rs6000_function_arg): Adjust. (rs6000_gimplify_va_arg): Pass false for that new parameter. --- gcc/config/rs6000/rs6000.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c index 8c06651..5230997 100644 --- a/gcc/config/rs6000/rs6000.c +++ b/gcc/config/rs6000/rs6000.c @@ -11192,11 +11192,13 @@ is_complex_IBM_long_double (machine_mode mode) registers. */ static bool -abi_v4_pass_in_fpr (machine_mode mode) +abi_v4_pass_in_fpr (machine_mode mode, bool named) { if (!TARGET_HARD_FLOAT) return false; - if (mode == SFmode || mode == DFmode) + if (mode == DFmode) + return true; + if (mode == SFmode && named) return true; /* ABI_V4 passes complex IBM long double in 8 gprs. Stupid, but we can't change the ABI now. */ @@ -11663,7 +11665,7 @@ rs6000_function_arg_advance_1 (CUMULATIVE_ARGS *cum, machine_mode mode, } else if (DEFAULT_ABI == ABI_V4) { - if (abi_v4_pass_in_fpr (mode)) + if (abi_v4_pass_in_fpr (mode, named)) { /* _Decimal128 must use an even/odd register pair. This assumes that the register number is odd when fregno is odd. */ @@ -12215,7 +12217,7 @@ rs6000_function_arg (cumulative_args_t cum_v, machine_mode mode, else if (abi == ABI_V4) { - if (abi_v4_pass_in_fpr (mode)) + if (abi_v4_pass_in_fpr (mode, named)) { /* _Decimal128 must use an even/odd register pair. This assumes that the register number is odd when fregno is odd. */ @@ -13136,7 +13138,7 @@ rs6000_gimplify_va_arg (tree valist, tree type, gimple_seq *pre_p, align = 1; machine_mode mode = TYPE_MODE (type); - if (abi_v4_pass_in_fpr (mode)) + if (abi_v4_pass_in_fpr (mode, false)) { /* FP args go in FP registers, if present. */ reg = fpr; -- 1.8.3.1