[PATCH] D27221: [AArch64] allow and-not-compare transform to form 'bics'

[Sanjay Patel via Phabricator via llvm-commits]

spatel created this revision.
spatel added reviewers: t.p.northover, mcrosier, gberry.
spatel added a subscriber: llvm-commits.
Herald added subscribers: rengolin, aemerson.

This target hook was added with https://reviews.llvm.org/D19087, and I expected AArch64 to enable it. But nobody has gotten to it yet, and this is blocking another and-not transform that I'd like to add.


https://reviews.llvm.org/D27221

Files:
  lib/Target/AArch64/AArch64ISelLowering.h
  test/CodeGen/AArch64/bics.ll


Index: test/CodeGen/AArch64/bics.ll
===================================================================
--- test/CodeGen/AArch64/bics.ll
+++ test/CodeGen/AArch64/bics.ll
@@ -13,13 +13,10 @@
   ret i1 %cmp
 }
 
-; FIXME: Recognize a disguised bics.
-
 define i1 @and_cmp(i32 %x, i32 %y) {
 ; CHECK-LABEL: and_cmp:
 ; CHECK:       // BB#0:
-; CHECK-NEXT:    and w8, w0, w1
-; CHECK-NEXT:    cmp w8, w1
+; CHECK-NEXT:    bics wzr, w1, w0
 ; CHECK-NEXT:    cset w0, eq
 ; CHECK-NEXT:    ret
 ;
@@ -32,8 +29,7 @@
 ; CHECK-LABEL: and_cmp_const:
 ; CHECK:       // BB#0:
 ; CHECK-NEXT:    mov w8, #43
-; CHECK-NEXT:    and w8, w0, w8
-; CHECK-NEXT:    cmp w8, #43
+; CHECK-NEXT:    bics wzr, w8, w0
 ; CHECK-NEXT:    cset w0, eq
 ; CHECK-NEXT:    ret
 ;
Index: lib/Target/AArch64/AArch64ISelLowering.h
===================================================================
--- lib/Target/AArch64/AArch64ISelLowering.h
+++ lib/Target/AArch64/AArch64ISelLowering.h
@@ -412,6 +412,11 @@
     return true;
   }
 
+  bool hasAndNotCompare(SDValue) const override {
+    // 'bics'
+    return true;
+  }
+
   bool hasBitPreservingFPLogic(EVT VT) const override {
     // FIXME: Is this always true? It should be true for vectors at least.
     return VT == MVT::f32 || VT == MVT::f64;


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