Hello,
this patch updates the prior version:
https://gcc.gnu.org/ml/gcc-patches/2014-07/msg00632.html
to add a -Wpsabi note as discussed.
(We may need to change the "GCC 4.10" string if the next release turns out
to get a different name ...)
In a testsuite run, this note triggers only in those two ABI compat suite
test cases mentioned in the previous patch email (only on ELFv2, of course).
Tested on powerpc64le-linux.
OK for mainline?
Bye,
Ulrich
gcc/testsuite/ChangLog:
* config/rs6000/rs6000.c (rs6000_function_arg): If a float argument
does not fit fully into floating-point registers, and there is still
space in the register parameter area, use GPRs to pass those parts
of the argument. Issue -Wpsabi note if any parameter is now treated
differently than before.
(rs6000_arg_partial_bytes): Update.
gcc/testsuite/ChangLog:
* gcc.target/powerpc/ppc64-abi-warn-2.c: New test.
Index: gcc/config/rs6000/rs6000.c
===================================================================
--- gcc/config/rs6000/rs6000.c (revision 212147)
+++ gcc/config/rs6000/rs6000.c (working copy)
@@ -10227,6 +10227,7 @@
rtx r, off;
int i, k = 0;
unsigned long n_fpreg = (GET_MODE_SIZE (elt_mode) + 7) >> 3;
+ int fpr_words;
/* Do we also need to pass this argument in the parameter
save area? */
@@ -10255,6 +10256,47 @@
rvec[k++] = gen_rtx_EXPR_LIST (VOIDmode, r, off);
}
+ /* If there were not enough FPRs to hold the argument, the rest
+ usually goes into memory. However, if the current position
+ is still within the register parameter area, a portion may
+ actually have to go into GPRs.
+
+ Note that it may happen that the portion of the argument
+ passed in the first "half" of the first GPR was already
+ passed in the last FPR as well.
+
+ For unnamed arguments, we already set up GPRs to cover the
+ whole argument in rs6000_psave_function_arg, so there is
+ nothing further to do at this point. */
+ fpr_words = (i * GET_MODE_SIZE (elt_mode)) / (TARGET_32BIT ? 4 : 8);
+ if (i < n_elts && align_words + fpr_words < GP_ARG_NUM_REG
+ && cum->nargs_prototype > 0)
+ {
+ static bool warned;
+
+ enum machine_mode rmode = TARGET_32BIT ? SImode : DImode;
+ int n_words = rs6000_arg_size (mode, type);
+
+ align_words += fpr_words;
+ n_words -= fpr_words;
+
+ do
+ {
+ r = gen_rtx_REG (rmode, GP_ARG_MIN_REG + align_words);
+ off = GEN_INT (fpr_words++ * GET_MODE_SIZE (rmode));
+ rvec[k++] = gen_rtx_EXPR_LIST (VOIDmode, r, off);
+ }
+ while (++align_words < GP_ARG_NUM_REG && --n_words != 0);
+
+ if (!warned && warn_psabi)
+ {
+ warned = true;
+ inform (input_location,
+ "the ABI of passing homogeneous float aggregates"
+ " has changed in GCC 4.10");
+ }
+ }
+
return rs6000_finish_function_arg (mode, rvec, k);
}
else if (align_words < GP_ARG_NUM_REG)
@@ -10330,8 +10372,23 @@
/* Otherwise, we pass in FPRs only. Check for partial copies. */
passed_in_gprs = false;
if (cum->fregno + n_elts * n_fpreg > FP_ARG_MAX_REG + 1)
- ret = ((FP_ARG_MAX_REG + 1 - cum->fregno)
- * MIN (8, GET_MODE_SIZE (elt_mode)));
+ {
+ /* Compute number of bytes / words passed in FPRs. If there
+ is still space available in the register parameter area
+ *after* that amount, a part of the argument will be passed
+ in GPRs. In that case, the total amount passed in any
+ registers is equal to the amount that would have been passed
+ in GPRs if everything were passed there, so we fall back to
+ the GPR code below to compute the appropriate value. */
+ int fpr = ((FP_ARG_MAX_REG + 1 - cum->fregno)
+ * MIN (8, GET_MODE_SIZE (elt_mode)));
+ int fpr_words = fpr / (TARGET_32BIT ? 4 : 8);
+
+ if (align_words + fpr_words < GP_ARG_NUM_REG)
+ passed_in_gprs = true;
+ else
+ ret = fpr;
+ }
}
if (passed_in_gprs
Index: gcc/testsuite/gcc.target/powerpc/ppc64-abi-warn-1.c
===================================================================
--- /dev/null
+++ gcc/testsuite/gcc.target/powerpc/ppc64-abi-warn-1.c (revision 0)
@@ -0,0 +1,12 @@
+/* { dg-do compile { target { powerpc*-*-linux* && lp64 } } } */
+/* { dg-options "-mabi=elfv2" } */
+
+struct f8
+ {
+ float x[8];
+ };
+
+void test (struct f8 a, struct f8 b) /* { dg-message "note: the ABI of passing
homogeneous float aggregates has changed" } */
+{
+}
+
--
Dr. Ulrich Weigand
GNU/Linux compilers and toolchain
ulrich.weig...@de.ibm.com
