link: run fpcast-emu before optimization passes#26478
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thiblahute wants to merge 1 commit intoemscripten-core:mainfrom
Open
link: run fpcast-emu before optimization passes#26478thiblahute wants to merge 1 commit intoemscripten-core:mainfrom
thiblahute wants to merge 1 commit intoemscripten-core:mainfrom
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sbc100
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I love the simplicity of the fix, but I wonder if we can come up with smaller/simpler test case?
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Indeed, I wrote the test case that was as close as possible with the actual trigger I had, simplified now. |
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Nice! I was hoping this would be faster, great to see that it is. It makes sense I guess - now all the casts use the same type, and any indirect call of a constant is optimizable.
Move the `--fpcast-emu` binaryen pass earlier in the pass pipeline so it runs before -O2. Previously, directize (part of -O2) would see type-mismatched call_indirect entries and replace them with unreachable before fpcast-emu had a chance to rewrite the table entries with matching types. This caused crashes for common C idioms like calling a 1-arg function through a 2-arg function pointer (e.g. GLib's `g_list_free_full` pattern). This reordering also improves performance: on a real-world GStreamer test binary, the reordered pipeline produces a 1.8% smaller wasm output (5.30MB vs 5.40MB) and seems to run almost ~2x faster (not sure why). Also move the fpcast-emu block outside `if optimizing:` so it runs even without -O2 in the link flags as this is not an optimization pass in practice. Also add a regression test. See WebAssembly/binaryen#8475
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Move the
--fpcast-emubinaryen pass earlier in the pass pipeline so it runs before -O2. Previously, directize (part of -O2) would see type-mismatched call_indirect entries and replace them with unreachable before fpcast-emu had a chance to rewrite the table entries with matching types. This caused crashes for common C idioms like calling a 1-arg function through a 2-arg function pointer (e.g. GLib'sg_list_free_fullpattern).This reordering also improves performance, on a real-world GStreamer test binary, the reordered pipeline produces a 1.8% smaller wasm output (5.30MB vs 5.40MB) and seems to run almost ~2x faster (not sure why).
Also move the fpcast-emu block outside
if optimizing:so it runs even without -O2 in the link flags as this is not an optimization pass in practice.Also add a regression test.
See WebAssembly/binaryen#8475