[AArch64] Change EON pattern to match more often.

Phabricator: http://reviews.llvm.org/D11359
Patch by Geoff Berry <gberry@codeaurora.org>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@242694 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/AArch64/AArch64InstrInfo.td b/lib/Target/AArch64/AArch64InstrInfo.td
index a30b78f6e2964035f970ec89564ad0e5165da885..867b95b566a63d4cf7aec43d54d0f43aacc8f1b8 100644 (file)
--- a/lib/Target/AArch64/AArch64InstrInfo.td
+++ b/lib/Target/AArch64/AArch64InstrInfo.td
@@ -841,7 +841,7 @@ defm AND  : LogicalReg<0b00, 0, "and", and>;
 defm BIC  : LogicalReg<0b00, 1, "bic",
                        BinOpFrag<(and node:$LHS, (not node:$RHS))>>;
 defm EON  : LogicalReg<0b10, 1, "eon",
-                       BinOpFrag<(xor node:$LHS, (not node:$RHS))>>;
+                       BinOpFrag<(not (xor node:$LHS, node:$RHS))>>;
 defm EOR  : LogicalReg<0b10, 0, "eor", xor>;
 defm ORN  : LogicalReg<0b01, 1, "orn",
                        BinOpFrag<(or node:$LHS, (not node:$RHS))>>;

diff --git a/test/CodeGen/AArch64/eon.ll b/test/CodeGen/AArch64/eon.ll
new file mode 100644 (file)
index 0000000..ea61ce3
--- /dev/null
+++ b/test/CodeGen/AArch64/eon.ll
@@ -0,0 +1,29 @@
+; RUN: llc -mtriple=aarch64-none-linux-gnu < %s | FileCheck %s
+
+; Check that the eon instruction is generated instead of eor,movn
+define i64 @test1(i64 %a, i64 %b, i64 %c) {
+; CHECK-LABEL: test1:
+; CHECK: eon
+; CHECK: ret
+entry:
+  %shl = shl i64 %b, 4
+  %neg = xor i64 %a, -1
+  %xor = xor i64 %shl, %neg
+  ret i64 %xor
+}
+
+; Same check with mutliple uses of %neg
+define i64 @test2(i64 %a, i64 %b, i64 %c) {
+; CHECK-LABEL: test2:
+; CHECK: eon
+; CHECK: eon
+; CHECK: lsl
+; CHECK: ret
+entry:
+  %shl = shl i64 %b, 4
+  %neg = xor i64 %shl, -1
+  %xor = xor i64 %neg, %a
+  %xor1 = xor i64 %c, %neg
+  %shl2 = shl i64 %xor, %xor1
+  ret i64 %shl2
+}