Add custom profile for debug builds with basic optimizations

Regular debug builds need to be debuggable according to the
principle of least surprise. This is also expected by tools.

There is a need for optimized builds with assertions enabled
so we add that as a custom profile instead.

.github/workflows/build-and-test-x86.yml

@@ -12,7 +12,7 @@ jobs:
           # release build without optimized assembly routines
           {name: "release", flags: "--release --no-default-features --features=bitdepth_8,bitdepth_16", timeout_multiplier: 1},
           # debug build to catch overflows with optimized assembly routines
-          {name: "debug", flags: "", timeout_multiplier: 2}
+          {name: "opt-dev", flags: "--profile opt-dev", timeout_multiplier: 2}
         ]
     runs-on: ubuntu-latest
     steps:

Cargo.toml

@@ -43,11 +43,10 @@ asm = []
 bitdepth_8 = []
 bitdepth_16 = []
 
-[profile.dev]
-# As we port, we increasingly use operations that require more optimizations to be zero-cost,
-# so while `--release` perf stays the same, debug perf suffers a lot,
-# unless we enable the basic optimizations (`opt-level = 1`),
-# which don't increase compile-time that much.
+[profile.opt-dev]
+# The debug builds run tests very slowly so this profile keeps debug assertions
+# while enabling basic optimizations. The profile is not suitable for debugging.
+inherits = "dev"
 opt-level = 1
 
 [profile.release]