pulley: Add some disas tests of suboptimal codegen patterns (#10101)

Author: alexcrichton

tests/disas/pulley/coremark-1.wat

@@ -0,0 +1,100 @@
+;;! target = "pulley64"
+;;! test = "compile"
+
+;; Small test of a loop extracted from "coremark-minimal.wasm"  here:
+;; https://github.com/wasmi-labs/wasmi-benchmarks/blob/d045a88246d3ac9b0b80b188feda54b89ca126b5/benches/res/wasm/coremark-minimal.wasm
+;;
+;; This doesn't reproduce the exact regalloc decisions but does currently show
+;; something suboptimal for Pulley which is at the end of the loop it's
+;; currently:
+;;
+;; * `br_if_not32` to exit the loop
+;; * `xmov` to move some registers in place
+;; * `jump` to resume the loop
+;;
+;; Ideally to minimize Pulley opcodes this would skip the `xmov` and `jump`
+;; with different register allocation and the back-edge would be a single
+;; conditional branch.
+
+(module
+  (memory 10)
+  (func (param $p1 i32) (param $p2 i32) (param $cnt i32)
+        (param $stride i32)
+        (result i32)
+    (local $accum i32)
+    loop
+      local.get $accum
+
+      local.get $p1
+      i32.load16_u
+      local.get $p2
+      i32.load16_u
+      i32.mul
+      local.tee $accum
+      i32.const 2
+      i32.shr_u
+      i32.const 15
+      i32.and
+      local.get $accum
+      i32.const 5
+      i32.shr_u
+      i32.const 127
+      i32.and
+      i32.mul
+      i32.add
+      local.set $accum
+
+      local.get $p2
+      i32.const 2
+      i32.add
+      local.set $p2
+
+      local.get $p1
+      local.get $stride
+      i32.add
+      local.set $p1
+
+      local.get $cnt
+      i32.const -1
+      i32.add
+      local.tee $cnt
+
+      br_if 0
+    end
+
+    call $other
+
+    (local.get $accum)
+  )
+
+  (func $other)
+)
+;; wasm[0]::function[0]:
+;;       push_frame_save 16, x16
+;;       xzero x6
+;;       xload64le_o32 x11, x0, 80
+;;       xload64le_o32 x13, x0, 88
+;;       xload16le_u32_g32 x12, x11, x13, x2, 0
+;;       xload16le_u32_g32 x13, x11, x13, x3, 0
+;;       xsub32_u8 x4, x4, 1
+;;       xmul32 x12, x12, x13
+;;       xshr32_u_u6 x13, x12, 2
+;;       xband32_s8 x13, x13, 15
+;;       xshr32_u_u6 x12, x12, 5
+;;       xband32_s8 x12, x12, 127
+;;       xmadd32 x6, x13, x12, x6
+;;       xmov x16, x6
+;;       xadd32 x2, x2, x5
+;;       xadd32_u8 x3, x3, 2
+;;       br_if_not32 x4, 0xe    // target = 0x53
+;;   4b: xmov x6, x16
+;;       jump -0x40    // target = 0xe
+;;   53: call2 x0, x0, 0x10    // target = 0x63
+;;       xmov x0, x16
+;;       pop_frame_restore 16, x16
+;;       ret
+;;
+;; wasm[0]::function[1]::other:
+;;       push_frame
+;;       pop_frame
+;;       ret

tests/disas/pulley/fib.wat

@@ -0,0 +1,71 @@
+;;! target = "pulley64"
+;;! test = "compile"
+
+;; Test of a recursive fibonacci routine and its codegen
+;;
+;; FIXME(#9942) this test currently has an extraneous `xmov` after the second
+;; call instruction.
+
+(module
+  (func $fib (export "fib") (param $n i32) (result i32)
+    (if (result i32)
+      (i32.eq
+        (i32.const 0)
+        (local.get $n)
+      )
+      (then
+        (i32.const 1)
+      )
+      (else
+        (if (result i32)
+          (i32.eq
+            (i32.const 1)
+            (local.get $n)
+          )
+          (then
+            (i32.const 1)
+          )
+          (else
+            (i32.add
+              ;; fib(n - 1)
+              (call $fib
+                (i32.add
+                  (local.get $n)
+                  (i32.const -1)
+                )
+              )
+              ;; fib(n - 2)
+              (call $fib
+                (i32.add
+                  (local.get $n)
+                  (i32.const -2)
+                )
+              )
+            )
+          )
+        )
+      )
+    )
+  )
+)
+;; wasm[0]::function[0]::fib:
+;;       push_frame_save 32, x17, x24, x29
+;;       br_if_xeq32_i8 x2, 0, 0x47    // target = 0x4c
+;;       br_if_xeq32_i8 x2, 1, 0x39    // target = 0x45
+;;   13: xsub32_u8 x14, x2, 1
+;;       xmov x24, x0
+;;       xmov x29, x2
+;;       call3 x24, x24, x14, -0x1d    // target = 0x0
+;;       xmov x17, x0
+;;       xmov x2, x29
+;;       xmov x0, x24
+;;       xsub32_u8 x14, x2, 2
+;;       call3 x0, x0, x14, -0x32    // target = 0x0
+;;       xmov x5, x17
+;;       xadd32 x0, x5, x0
+;;       jump 0xe    // target = 0x4e
+;;   45: xone x0
+;;       jump 0x7    // target = 0x4e
+;;   4c: xone x0
+;;       pop_frame_restore 32, x17, x24, x29
+;;       ret