PING**2 for the ME review or at least comments to that patch, which fixes a build issue/ICE with nvptx (at least when bumping the default -misa).
Patch: https://gcc.gnu.org/pipermail/gcc-patches/2022-February/590139.html (for gcc/cfgexpand.cc + gcc/expr.cc) (There is some discussion by Tom and Roger about the BE in the patch thread, which only not relate to the ME patch. But there is no ME-patch comment so far.) Thanks, Tobias On 17.02.22 15:35, Tobias Burnus wrote:
PING for this cfgexpand.cc + expr.cc change by Roger. This is a pre-requisite for Roger's nvptx patch to avoid an ICE during bootstrap: * https://gcc.gnu.org/pipermail/gcc-patches/2022-February/590250.html "[PATCH] nvptx: Back-end portion of a fix for PR target/104489." (see patch for additional reasoning for this patch) * See also https://gcc.gnu.org/PR104489 nvptx, sm_53: internal compiler error: in gen_rtx_SUBREG, at emit-rtl.cc:1022 Thanks, Tobias On 09.02.22 21:12, Roger Sayle wrote:This patch adds middle-end support for target ABIs that pass/return floating point values in integer registers with precision wider than the original FP mode. An example, is the nvptx backend where 16-bit HFmode registers are passed/returned as (promoted to) SImode registers. Unfortunately, this currently falls foul of the various (recent?) sanity checks that (very sensibly) prevent creating paradoxical SUBREGs of floating point registers. The approach below is to explicitly perform the conversion/promotion in two steps, via an integer mode of same precision as the floating point value. So on nvptx, 16-bit HFmode is initially converted to 16-bit HImode (using SUBREG), then zero-extended to SImode, and likewise when going the other way, parameters truncated to HImode then converted to HFmode (using SUBREG). These changes are localized to expand_value_return and expanding DECL_RTL to support strange ABIs, rather than inside convert_modes or gen_lowpart, as mismatched precision integer/FP conversions should be explicit in the RTL, and these semantics not generally visible/implicit in user code. This patch has been tested on x86_64-pc-linux-gnu with make bootstrap and make -k check with no new failures, and on nvptx-none, where it is the middle-end portion of a pair of patches to allow the default ISA to be advanced. Ok for mainline? 2022-02-09 Roger Sayle <ro...@nextmovesoftware.com> gcc/ChangeLog * cfgexpand.cc (expand_value_return): Allow backends to promote a scalar floating point return value to a wider integer mode. * expr.cc (expand_expr_real_1) [expand_decl_rtl]: Likewise, allow backends to promote scalar FP PARM_DECLs to wider integer modes. Thanks in advance, Roger --
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