Merging r230742:

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r230742 | vkalintiris | 2015-02-27 09:01:39 +0000 (Fri, 27 Feb 2015) | 12 lines

[mips] Account for constant-zero operands in ADDE nodes.

Summary:
We identify the cases where the operand to an ADDE node is a constant
zero. In such cases, we can avoid generating an extra ADDu instruction
disguised as an identity move alias (ie. addu $r, $r, 0 --> move $r, $r).

Reviewers: dsanders

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D7906
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_36@235874 91177308-0d34-0410-b5e6-96231b3b80d8

test/CodeGen/Mips/check-adde-redundant-moves.ll

@@ -0,0 +1,29 @@
+; RUN: llc < %s -march=mips -mcpu=mips2 | FileCheck %s \
+; RUN:    -check-prefix=ALL -check-prefix=GP32
+; RUN: llc < %s -march=mips -mcpu=mips32 | FileCheck %s \
+; RUN:    -check-prefix=ALL -check-prefix=GP32
+; RUN: llc < %s -march=mips -mcpu=mips32r2 | FileCheck %s \
+; RUN:    -check-prefix=ALL -check-prefix=GP32
+; RUN: llc < %s -march=mips -mcpu=mips32r6 | FileCheck %s \
+; RUN:    -check-prefix=ALL -check-prefix=GP32
+; RUN: llc < %s -march=mips64 -mcpu=mips3 | FileCheck %s -check-prefix=ALL
+; RUN: llc < %s -march=mips64 -mcpu=mips4 | FileCheck %s -check-prefix=ALL
+; RUN: llc < %s -march=mips64 -mcpu=mips64 | FileCheck %s -check-prefix=ALL
+; RUN: llc < %s -march=mips64 -mcpu=mips64r2 | FileCheck %s -check-prefix=ALL
+; RUN: llc < %s -march=mips64 -mcpu=mips64r6 | FileCheck %s -check-prefix=ALL
+
+define i64 @add_i64(i64 %a) {
+  ; GP32-LABEL: add_i64
+
+  ; GP32-NOT:    move $[[T0:[0-9]+]], $[[T0]]
+  %r = add i64 5, %a
+  ret i64 %r
+}
+
+define i128 @add_i128(i128 %a) {
+  ; ALL-LABEL: add_i128
+
+  ; ALL-NOT:    move $[[T0:[0-9]+]], $[[T0]]
+  %r = add i128 5, %a
+  ret i128 %r
+}