craneleft: cancel ineg when args to imul (#6053)

* craneleft: cancel `ineg`/`iabs` when args to `imul` * Remove unsound `iabs(x) * iabs(y) == x*y` rewrite
2023-03-17 19:41:20 +00:00
parent 2e48babf23
commit c3f5b71b6a
2 changed files with 14 additions and 0 deletions
--- a/cranelift/filetests/filetests/egraph/algebraic.clif
+++ b/cranelift/filetests/filetests/egraph/algebraic.clif
@@ -232,6 +232,16 @@ block0(v0: i32):
    ; check: return v0
 }

+function %imul_ineg_cancel(i32, i32) -> i32 {
+block0(v0: i32, v1: i32):
+    v2 = ineg v0
+    v3 = ineg v1
+    v4 = imul v2, v3
+    return v4
+    ; check: v5 = imul v0, v1
+    ; check: return v5
+}
+
 function %isub_self(i32) -> i32 {
 block0(v0: i32):
    v1 = isub v0, v0