The continuing block can exit the loop in very constrained ways:
When a break statement is placed such that it would exit from a loop’s
§ 7.3.8 Continuing Statement, then:
- The break statement must appear as either:
- The only statement in the if clause of an if statement that has:
- no else clause or an empty else clause
- no elseif clauses
- The only statement in the else clause of an if statement that has an
empty if clause and no elseif clauses.
- That if statement must appear last in the continuing clause.
By design, this allows a lossless round-trip from SPIR-V to WGSL and
back to SPIR-V. But that requires this special case construct in WGSL
to be translated to an OpBranchConditional with one target being
the loop's megre block (which is where 'break' branches to), and the
other targets the loop header (which is the loop backedge). That
OpBranchConditional takes the place of the normal case of an
unconditional backedge.
Avoids errors like this:
continue construct with the continue target X is not
post dominated by the back-edge block Y
Fixed: 1034
Change-Id: If472a179380b8d77af746a3cd8e279c8a5e56b37
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/59800
Auto-Submit: David Neto <dneto@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: David Neto <dneto@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
This adds SPIR-V assembly and WGSL tests derived from VK-GL-CTS commit
571256871c2e2f03995373e1e4a02958d8cd8cf5. The following procedure was
followed:
- Those .amber files in VK-GL-CTS wholly owned by Google were
identified
- All GLSL and SPIR-V shaders were extracted from the Amber files and
converted into SPIR-V binaries
- The compact-ids pass of spirv-opt was applied to each binary
- Duplicate binaries were removed
- spirv-opt -O was used to obtain an optimized version of each remaining
binary, with duplicates discarded
- Binaries that failed validation using spirv-val with target
environment SPIR-V 1.3 were discarded
- Those binaries that tint could not successfully convert into WGSL were
put aside for further investigation
- SPIR-V assembly versions of the remaining binaries are included in
this CL
- test-runner with -generate-expected and -generate-skip was used to
generate expected .spvasm, .msl, .hlsl and .wgsl outputs for these
SPIR-V assembly tests
- Each successfully-generated .expected.wgsl is included in this CL
again, as a WGLSL test
- test-runner with -generate-expected and -generate-skip was used again,
to generate expected outputs for these WGSL tests
Change-Id: Ibe9baf2729cf97e0b633db9a426f53362a5de540
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/58842
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
David Neto
Alastair Donaldson