IR: handle control flow constructs (#186)

* IR: handle control flow constructs

This change includes a bunch of fixes and additions to the IR path:

- `slang-ir-assembly` is now a valid output target (so we can use it for testing)
  - This uses what used to be the IR "dumping" logic, revamped to support much prettier output.
  - A future change will need to add back support for less prettified output to use when actually debugging

- IR generation for `for` loops and `if` statements is supported

- HLSL output from the above control flow constructs is implemented

- Revamped the handling of l-values, and in particular work on compound ops like `+=`

- Add basic IR support for `groupshared` variables

- Add basic IR support for storing compute thread-group size

- Output semantics on entry point parameters
  - This uses the AST structures to find semantics, so its still needs work

- Pass through loop unroll flags
  - This is required to match `fxc` output, at least until we implement
    unrolling ourselves.

* Fixup: 64-bit build issues.

* fixup for merge

1 files changed, 33 insertions, 0 deletions

diff --git a/tests/ir/loop.slang b/tests/ir/loop.slang
new file mode 100644
index 000000000..d637e4536
--- /dev/null
+++ b/tests/ir/loop.slang
@@ -0,0 +1,33 @@
+//TEST:SIMPLE:-target slang-ir-assembly -profile cs_4_0 -entry main
+
+#define GROUP_THREAD_COUNT 64
+
+StructuredBuffer<float4> input;
+RWStructuredBuffer<float4> output;
+
+groupshared float4 s[GROUP_THREAD_COUNT];
+
+[numthreads(GROUP_THREAD_COUNT, 1, 1)]
+void main(
+    uint dispatchThreadID   : SV_DispatchThreadIndex,
+    uint groupThreadID      : SV_GroupThreadIndex,
+    uint groupID            : SV_GroupIndex )
+{
+    // the actual algorithm being done here is bogus
+
+    // load shared memory
+    s[groupThreadID] = input[dispatchThreadID];
+
+    // do some sum passes
+    for(uint stride = 1; stride < GROUP_THREAD_COUNT; stride <<= 1)
+    {
+        GroupMemoryBarrierWithGroupSync();
+
+        s[groupThreadID] += s[groupThreadID - stride];
+    }
+
+    GroupMemoryBarrierWithGroupSync();
+
+    output[dispatchThreadID] = s[0];
+}
+