Make it possible to test the generated assembly

This test framework feature is inspired by a similar feature in LLVM.
The programmer writes a bit of Cmm

    #include "Cmm.h"

    // Large memcpy's should lower to calls.
    callMemcpy
    {
      W_ dst, src;
      prim %memcpy(dst "ptr", src "ptr", 1024, 4) [];
    }

and asserts what the generated assembly should look like, modulo
register naming.

    callMemcpy:
    movq  ; Move arguments into place
    movq
    movl
    movl
    call memcpy

Patch edited and updated by Simon Marlow, and I also added a test for
unrolling memcpy and a simple constant-propagation test.

1 files changed, 8 insertions, 0 deletions

diff --git a/testsuite/tests/codeGen/should_gen_asm/memcpy-unroll.cmm b/testsuite/tests/codeGen/should_gen_asm/memcpy-unroll.cmm
new file mode 100644
index 0000000000..95656b4410
--- /dev/null
+++ b/testsuite/tests/codeGen/should_gen_asm/memcpy-unroll.cmm
@@ -0,0 +1,8 @@
+#include "Cmm.h"
+
+// Small memcpies should unroll
+callMemcpy (W_ dst, W_ src)
+{
+  prim %memcpy(dst, src, 16, 4);
+  return ();
+}