[llvm] r245640 - AArch64: Do not create CCMP on multiple users.

[Matthias Braun via llvm-commits]

Author: matze
Date: Thu Aug 20 18:33:31 2015
New Revision: 245640

URL: http://llvm.org/viewvc/llvm-project?rev=245640&view=rev
Log:
AArch64: Do not create CCMP on multiple users.

Create CMP;CCMP sequences from and/or trees does not gain us anything if
the and/or tree is materialized to a GP register anyway. While most of
the code already checked for hasOneUse() there was one important case
missing.

Modified:
    llvm/trunk/lib/Target/AArch64/AArch64ISelLowering.cpp
    llvm/trunk/test/CodeGen/AArch64/arm64-ccmp.ll

Modified: llvm/trunk/lib/Target/AArch64/AArch64ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AArch64/AArch64ISelLowering.cpp?rev=245640&r1=245639&r2=245640&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/AArch64/AArch64ISelLowering.cpp Thu Aug 20 18:33:31 2015
@@ -1349,7 +1349,7 @@ static SDValue emitConjunctionDisjunctio
     unsigned NZCV = AArch64CC::getNZCVToSatisfyCondCode(InvOutCC);
     return emitConditionalComparison(LHS, RHS, CC, CCOp, ConditionOp, NZCV, DL,
                                      DAG);
-  } else if (Opcode != ISD::AND && Opcode != ISD::OR)
+  } else if ((Opcode != ISD::AND && Opcode != ISD::OR) || !Val->hasOneUse())
     return SDValue();
 
   assert((Opcode == ISD::OR || !PushNegate)

Modified: llvm/trunk/test/CodeGen/AArch64/arm64-ccmp.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AArch64/arm64-ccmp.ll?rev=245640&r1=245639&r2=245640&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/AArch64/arm64-ccmp.ll (original)
+++ llvm/trunk/test/CodeGen/AArch64/arm64-ccmp.ll Thu Aug 20 18:33:31 2015
@@ -373,8 +373,8 @@ define i32 @select_ororand(i32 %w0, i32
   ret i32 %sel
 }
 
-; CHECK-LABEL: select_noccmp
-define i64 @select_noccmp(i64 %v1, i64 %v2, i64 %v3, i64 %r) {
+; CHECK-LABEL: select_noccmp1
+define i64 @select_noccmp1(i64 %v1, i64 %v2, i64 %v3, i64 %r) {
 ; CHECK-NOT: CCMP
   %c0 = icmp slt i64 %v1, 0
   %c1 = icmp sgt i64 %v1, 13
@@ -386,3 +386,19 @@ define i64 @select_noccmp(i64 %v1, i64 %
   %sel = select i1 %or, i64 0, i64 %r
   ret i64 %sel
 }
+
+ at g = global i32 0
+
+; Should not use ccmp if we have to compute the or expression in an integer
+; register anyway because of other users.
+; CHECK-LABEL: select_noccmp2
+define i64 @select_noccmp2(i64 %v1, i64 %v2, i64 %v3, i64 %r) {
+; CHECK-NOT: CCMP
+  %c0 = icmp slt i64 %v1, 0
+  %c1 = icmp sgt i64 %v1, 13
+  %or = or i1 %c0, %c1
+  %sel = select i1 %or, i64 0, i64 %r
+  %ext = sext i1 %or to i32
+  store volatile i32 %ext, i32* @g
+  ret i64 %sel
+}