Add Om1 lowering with no optimizations.
This adds infrastructure for low-level x86-32 instructions, and the target lowering patterns.
Practically no optimizations are performed. Optimizations to be introduced later include liveness analysis, dead-code elimination, global linear-scan register allocation, linear-scan based stack slot coalescing, and compare/branch fusing. One optimization that is present is simple coalescing of stack slots for variables that are only live within a single basic block.
There are also some fairly comprehensive cross tests. This testing infrastructure translates bitcode using both Subzero and llc, and a testing harness calls both versions with a variety of "interesting" inputs and compares the results. Specifically, Arithmetic, Icmp, Fcmp, and Cast instructions are tested this way, across all PNaCl primitive types.
BUG=
R=jvoung@chromium.org
Review URL: https://codereview.chromium.org/265703002
diff --git a/.gitignore b/.gitignore
index a19ccde..0d1d959 100644
--- a/.gitignore
+++ b/.gitignore
@@ -10,3 +10,4 @@
# Ignore specific patterns at the top-level directory
/llvm2ice
/build/
+/crosstest/Output/
