Cranelift: GVN uadd_overflow_trap (#5520)

* Switch duplicate loads w/ dynamic memories test to `min_size = 0`

This test was accidentally hitting a special case for bounds checks for when we
know that `offset + access_size < min_size` and can skip some steps. This
commit changes the `min_size` of the memory to zero so that we are forced to do
fully general bounds checks.

* Cranelift: Mark `uadd_overflow_trap` as okay for GVN

Although this improves our test sequence for duplicate loads with dynamic
memories, it unfortunately doesn't have any effect on sightglass benchmarks:

```
instantiation :: instructions-retired :: benchmarks/pulldown-cmark/benchmark.wasm

  No difference in performance.

  [34448 35607.23 37158] gvn_uadd_overflow_trap.so
  [34566 35734.05 36585] main.so

instantiation :: instructions-retired :: benchmarks/spidermonkey/benchmark.wasm

  No difference in performance.

  [44101 60449.62 92712] gvn_uadd_overflow_trap.so
  [44011 60436.37 92690] main.so

instantiation :: instructions-retired :: benchmarks/bz2/benchmark.wasm

  No difference in performance.

  [35595 36675.72 38153] gvn_uadd_overflow_trap.so
  [35440 36670.42 37993] main.so

compilation :: instructions-retired :: benchmarks/bz2/benchmark.wasm

  No difference in performance.

  [17370195 17405125.62 17471222] gvn_uadd_overflow_trap.so
  [17369324 17404859.43 17470725] main.so

execution :: instructions-retired :: benchmarks/spidermonkey/benchmark.wasm

  No difference in performance.

  [7055720520 7055886880.32 7056265930] gvn_uadd_overflow_trap.so
  [7055719554 7055843809.33 7056193289] main.so

compilation :: instructions-retired :: benchmarks/spidermonkey/benchmark.wasm

  No difference in performance.

  [683589861 683767276.00 684098366] gvn_uadd_overflow_trap.so
  [683590024 683767998.02 684097885] main.so

execution :: instructions-retired :: benchmarks/pulldown-cmark/benchmark.wasm

  No difference in performance.

  [46436883 46437135.10 46437823] gvn_uadd_overflow_trap.so
  [46436883 46437087.67 46437785] main.so

compilation :: instructions-retired :: benchmarks/pulldown-cmark/benchmark.wasm

  No difference in performance.

  [126522461 126565812.58 126647044] gvn_uadd_overflow_trap.so
  [126522176 126565757.75 126647522] main.so

execution :: instructions-retired :: benchmarks/bz2/benchmark.wasm

  No difference in performance.

  [653010531 653010533.03 653010544] gvn_uadd_overflow_trap.so
  [653010531 653010533.18 653010537] main.so
```

* cranelift-codegen-meta: Rename `side_effects_okay_for_gvn` to `side_effects_idempotent`

* cranelift-filetests: Ensure there is a trailing newline for blessed Wasm tests
This commit is contained in:
Nick Fitzgerald
2023-01-04 22:03:16 -08:00
committed by GitHub
parent b46ad1b54d
commit f4a2d5337a
6 changed files with 67 additions and 64 deletions

View File

@@ -514,9 +514,9 @@ fn gen_opcodes(all_inst: &AllInstructions, fmt: &mut Formatter) {
);
gen_bool_accessor(
all_inst,
|inst| inst.side_effects_okay_for_gvn,
"side_effects_okay_for_gvn",
"Despite `self.other_side_effects() == true`, is this instruction okay to GVN?",
|inst| inst.side_effects_idempotent,
"side_effects_idempotent",
"Despite having side effects, is this instruction okay to GVN?",
fmt,
)
});