Thomas Lively 8df30d988e [WebAssembly] Do not omit range checks for i64 switches ...

Summary:
Since the br_table instruction takes an i32, switches over i64s (and
larger integers) must use the i32.wrap_i64 instruction to truncate the
table index. This truncation makes numbers just over 2^32
indistinguishable from small numbers, so it was a miscompilation to
omit the range check preceding these br_tables. This change fixes the
problem by skipping the "fixing" of the br_table when the range check
is an i64 instruction.

Fixes PR46447.

Reviewers: aheejin, dschuff, kripken

Reviewed By: kripken

Subscribers: sbc100, jgravelle-google, hiraditya, sunfish, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D83017

2020-07-03 17:15:39 -07:00

5.9 KiB

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