SelectionDAG: Add sext_inreg optimizations

v2: use dyn_cast
    fixup comments
v3: use cast

Reviewed-by: Matt Arsenault <arsenm2@gmail.com>
Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220044 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 76442fbda936e0cf1a7e6fb6d6a49fdf3bee212f..c131599931e7472332b22b9815cbb71c91446627 100644 (file)
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -1680,6 +1680,17 @@ SDValue DAGCombiner::visitADD(SDNode *N) {
     return DAG.getNode(ISD::SUB, DL, VT, N1, ZExt);
   }
 
+  // add X, (sextinreg Y i1) -> sub X, (and Y 1)
+  if (N1.getOpcode() == ISD::SIGN_EXTEND_INREG) {
+    VTSDNode *TN = cast<VTSDNode>(N1.getOperand(1));
+    if (TN->getVT() == MVT::i1) {
+      SDLoc DL(N);
+      SDValue ZExt = DAG.getNode(ISD::AND, DL, VT, N1.getOperand(0),
+                                 DAG.getConstant(1, VT));
+      return DAG.getNode(ISD::SUB, DL, VT, N0, ZExt);
+    }
+  }
+
   return SDValue();
 }
 
@@ -1845,6 +1856,17 @@ SDValue DAGCombiner::visitSUB(SDNode *N) {
                                  VT);
     }
 
+  // sub X, (sextinreg Y i1) -> add X, (and Y 1)
+  if (N1.getOpcode() == ISD::SIGN_EXTEND_INREG) {
+    VTSDNode *TN = cast<VTSDNode>(N1.getOperand(1));
+    if (TN->getVT() == MVT::i1) {
+      SDLoc DL(N);
+      SDValue ZExt = DAG.getNode(ISD::AND, DL, VT, N1.getOperand(0),
+                                 DAG.getConstant(1, VT));
+      return DAG.getNode(ISD::ADD, DL, VT, N0, ZExt);
+    }
+  }
+
   return SDValue();
 }
 

diff --git a/test/CodeGen/R600/sext-eliminate.ll b/test/CodeGen/R600/sext-eliminate.ll
new file mode 100644 (file)
index 0000000..7dc6eb8
--- /dev/null
+++ b/test/CodeGen/R600/sext-eliminate.ll
@@ -0,0 +1,26 @@
+; RUN: llc -march=r600 -mcpu=cypress -verify-machineinstrs < %s | FileCheck -check-prefix=EG -check-prefix=FUNC %s
+
+
+; FUNC-LABEL: {{^}}sext_in_reg_i1_i32_add:
+
+; EG: MEM_{{.*}} STORE_{{.*}} [[RES:T[0-9]+\.[XYZW]]], [[ADDR:T[0-9]+.[XYZW]]]
+; EG: SUB_INT {{[* ]*}}[[RES]]
+; EG-NOT: BFE
+define void @sext_in_reg_i1_i32_add(i32 addrspace(1)* %out, i1 %a, i32 %b) {
+  %sext = sext i1 %a to i32
+  %res = add i32 %b, %sext
+  store i32 %res, i32 addrspace(1)* %out
+  ret void
+}
+
+; FUNC-LABEL: {{^}}sext_in_reg_i1_i32_sub:
+
+; EG: MEM_{{.*}} STORE_{{.*}} [[RES:T[0-9]+\.[XYZW]]], [[ADDR:T[0-9]+.[XYZW]]]
+; EG: ADD_INT {{[* ]*}}[[RES]]
+; EG-NOT: BFE
+define void @sext_in_reg_i1_i32_sub(i32 addrspace(1)* %out, i1 %a, i32 %b) {
+  %sext = sext i1 %a to i32
+  %res = sub i32 %b, %sext
+  store i32 %res, i32 addrspace(1)* %out
+  ret void
+}