| Summary: | [i965] brw_fs_copy_propagation.cpp:432:21: error: variable length array of non-POD | ||
|---|---|---|---|
| Product: | Mesa | Reporter: | Vinson Lee <vlee> |
| Component: | Drivers/DRI/i965 | Assignee: | Kenneth Graunke <kenneth> |
| Status: | RESOLVED FIXED | QA Contact: | |
| Severity: | blocker | ||
| Priority: | medium | CC: | eric, idr |
| Version: | git | Keywords: | regression |
| Hardware: | x86-64 (AMD64) | ||
| OS: | Linux (All) | ||
| Whiteboard: | |||
| i915 platform: | i915 features: | ||
| Attachments: | A workaround to make it compile with Clang | ||
6a514494fa4c45e921bd6af7f3187a67c1e8d9d2 is the first bad commit commit 6a514494fa4c45e921bd6af7f3187a67c1e8d9d2 Author: Eric Anholt <eric@anholt.net> Date: Fri Sep 21 16:06:17 2012 +0200 i965/fs: Improve performance of copy/constant propagation. Use a simple chaining hash table for the ACP. This is not really very good, because we still do a full walk of the tree per destination write, but it still reduces fp-long-alu runtime from 5.3 to 3.9s. Reviewed-by: Kenneth Graunke <kenneth@whitecape.org> :040000 040000 a3a95c5b01ef5f860d4df61d2e46f41c2dfed611 3881d6355ee5ba71e0f84184ad718ca4a16934d7 M src bisect run success I actually think this is a compiler bug. exec_lists have no virtual methods, so they should be POD. Created attachment 72666 [details] [review] A workaround to make it compile with Clang I agree with Ian---I think it's a Clang bug. I've attached a patch which works around the issue. I don't know if we should apply it or try to work with upstream. Ian, Eric? Well, Matt was the only one that expressed an opinion, and I think it's worth fixing this, so I've pushed the fix: commit 2c4ad502ce12259160be6c73ebdd6e73a5d27c6f Author: Kenneth Graunke <kenneth@whitecape.org> Date: Tue Jan 8 12:46:05 2013 -0800 i965: Fix build error with clang. Technically, variable sized arrays are a required feature of C99, redacted to be optional in C11, and not actually part of C++ whatsoever. Gcc allows using them in C++ unless you specify -pedantic, and Clang appears to allow them for simple/POD types. exec_list is arguably POD, since it doesn't have virtual methods, but I can see why Clang would be like "meh, it's a C++ struct, say no", seeing as it's meant to support C99. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=58970 Reviewed-by: Matt Turner <mattst88@gmail.com> |
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mesa: 622d96aae499445f12861214354a5b9f63e3a738 (master) Build i965 with clang. $ make [...] CXX brw_fs_copy_propagation.lo clang: warning: argument unused during compilation: '-fno-builtin-memcmp' brw_fs_copy_propagation.cpp:41:1: warning: 'acp_entry' defined as a struct here but previously declared as a class [-Wmismatched-tags] struct acp_entry : public exec_node { ^ ./brw_fs.h:55:4: note: did you mean struct here? class acp_entry; ^~~~~ struct brw_fs_copy_propagation.cpp:432:21: error: variable length array of non-POD element type 'exec_list' exec_list out_acp[cfg.num_blocks][ACP_HASH_SIZE];