[GlobalISel] Only merge memory ops for mayLoad or mayStore instrs.

Summary:
We only need to merge memory operands for instructions that access
 memory. This slightly reduces the number of actions executed. 

Reviewers: MatzeB, rovka, dsanders

Reviewed By: dsanders

Subscribers: aemerson, igorb, kristof.beyls, llvm-commits

Differential Revision: https://reviews.llvm.org/D36151

llvm-svn: 309944

2 files changed, 25 insertions, 34 deletions

diff --git a/llvm/test/TableGen/GlobalISelEmitter.td b/llvm/test/TableGen/GlobalISelEmitter.td
index 11400d8f6ae..638fe48f10d 100644
--- a/llvm/test/TableGen/GlobalISelEmitter.td
+++ b/llvm/test/TableGen/GlobalISelEmitter.td
@@ -117,8 +117,7 @@ def HasC : Predicate<"Subtarget->hasC()"> { let RecomputePerFunction = 1; }
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/1, // src1
 // CHECK-NEXT:    GIR_ComplexRenderer, /*InsnID*/0, /*RendererID*/1,
 // CHECK-NEXT:    GIR_ComplexRenderer, /*InsnID*/0, /*RendererID*/0,
-// CHECK-NEXT:    GIR_MergeMemOperands, /*InsnID*/0, /*MergeInsnID's*/0, GIU_MergeMemOperands_EndOfList,
-// CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
+// CHECK-NEXT:    GIR_MergeMemOperands, /*InsnID*/0, /*MergeInsnID's*/0, GIU_MergeMemOperands_EndOfList, GIR_EraseFromParent, /*InsnID*/0,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
 // CHECK-NEXT:  // Label 0: @[[LABEL]]
@@ -168,14 +167,15 @@ def : Pat<(select GPR32:$src1, complex:$src2, (select GPR32:$src3, complex:$src4
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/1, /*OpIdx*/1, // src3
 // CHECK-NEXT:    GIR_ComplexRenderer, /*InsnID*/0, /*RendererID*/1,
 // CHECK-NEXT:    GIR_ComplexRenderer, /*InsnID*/0, /*RendererID*/2,
-// CHECK-NEXT:    GIR_MergeMemOperands, /*InsnID*/0, /*MergeInsnID's*/0, 1, GIU_MergeMemOperands_EndOfList,
 // CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
 // CHECK-NEXT:  // Label 1: @[[LABEL]]
 
 def : GINodeEquiv<G_SELECT, select>;
-def INSN2 : I<(outs GPR32:$dst), (ins GPR32Op:$src1, complex:$src2, complex:$src3), []>;
+let mayLoad = 1 in {
+  def INSN2 : I<(outs GPR32:$dst), (ins GPR32Op:$src1, complex:$src2, complex:$src3), []>;
+}
 def : Pat<(select GPR32:$src1, complex:$src2, complex:$src3),
           (INSN2 GPR32:$src1, complex:$src3, complex:$src2)>;
 
@@ -221,7 +221,6 @@ def ADD : I<(outs GPR32:$dst), (ins GPR32:$src1, GPR32:$src2),
 // CHECK-NEXT:    GIR_BuildMI, /*InsnID*/0, /*Opcode*/MyTarget::MOV,
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/0, // dst
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/2, // src1
-// CHECK-NEXT:    GIR_MergeMemOperands, /*InsnID*/0, /*MergeInsnID's*/0, GIU_MergeMemOperands_EndOfList,
 // CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
@@ -262,7 +261,6 @@ def MOV : I<(outs GPR32:$dst), (ins GPR32:$src1),
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/1, /*OpIdx*/1, // src1
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/1, /*OpIdx*/2, // src2
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/2, // src3
-// CHECK-NEXT:    GIR_MergeMemOperands, /*InsnID*/0, /*MergeInsnID's*/0, 1, GIU_MergeMemOperands_EndOfList,
 // CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
@@ -299,7 +297,6 @@ def MOV : I<(outs GPR32:$dst), (ins GPR32:$src1),
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/1, /*OpIdx*/1, // src1
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/1, /*OpIdx*/2, // src2
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/1, // src3
-// CHECK-NEXT:    GIR_MergeMemOperands, /*InsnID*/0, /*MergeInsnID's*/0, 1, GIU_MergeMemOperands_EndOfList,
 // CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
@@ -330,7 +327,6 @@ def MULADD : I<(outs GPR32:$dst), (ins GPR32:$src1, GPR32:$src2, GPR32:$src3),
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/0, // dst
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/2, // src2
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/1, // src1
-// CHECK-NEXT:    GIR_MergeMemOperands, /*InsnID*/0, /*MergeInsnID's*/0, GIU_MergeMemOperands_EndOfList,
 // CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
@@ -384,7 +380,6 @@ def MUL : I<(outs GPR32:$dst), (ins GPR32:$src2, GPR32:$src1),
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/1, /*OpIdx*/2, // src2
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/2, /*OpIdx*/1, // src3
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/2, /*OpIdx*/2, // src4
-// CHECK-NEXT:    GIR_MergeMemOperands, /*InsnID*/0, /*MergeInsnID's*/0, 1, 2, GIU_MergeMemOperands_EndOfList,
 // CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
@@ -415,7 +410,6 @@ def INSNBOB : I<(outs GPR32:$dst), (ins GPR32:$src1, GPR32:$src2, GPR32:$src3, G
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/0, // dst
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/1, // src1
 // CHECK-NEXT:    GIR_ComplexRenderer, /*InsnID*/0, /*RendererID*/0,
-// CHECK-NEXT:    GIR_MergeMemOperands, /*InsnID*/0, /*MergeInsnID's*/0, GIU_MergeMemOperands_EndOfList,
 // CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
@@ -444,7 +438,6 @@ def : Pat<(sub GPR32:$src1, complex:$src2), (INSN1 GPR32:$src1, complex:$src2)>;
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/0, // dst
 // CHECK-NEXT:    GIR_AddImm, /*InsnID*/0, /*Imm*/-1,
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/1, // src1
-// CHECK-NEXT:    GIR_MergeMemOperands, /*InsnID*/0, /*MergeInsnID's*/0, GIU_MergeMemOperands_EndOfList,
 // CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
@@ -474,7 +467,6 @@ def XORI : I<(outs GPR32:$dst), (ins m1:$src2, GPR32:$src1),
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/0, // dst
 // CHECK-NEXT:    GIR_AddRegister, /*InsnID*/0, MyTarget::R0,
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/1, // src1
-// CHECK-NEXT:    GIR_MergeMemOperands, /*InsnID*/0, /*MergeInsnID's*/0, GIU_MergeMemOperands_EndOfList,
 // CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
@@ -505,7 +497,6 @@ def XOR : I<(outs GPR32:$dst), (ins Z:$src2, GPR32:$src1),
 // CHECK-NEXT:    GIR_AddImm, /*InsnID*/0, /*Imm*/-1,
 // CHECK-NEXT:    GIR_AddRegister, /*InsnID*/0, MyTarget::R0,
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/1, // src1
-// CHECK-NEXT:    GIR_MergeMemOperands, /*InsnID*/0, /*MergeInsnID's*/0, GIU_MergeMemOperands_EndOfList,
 // CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
@@ -537,7 +528,6 @@ def XORlike : I<(outs GPR32:$dst), (ins m1Z:$src2, GPR32:$src1),
 // CHECK-NEXT:    GIR_AddRegister, /*InsnID*/0, MyTarget::R0,
 // CHECK-NEXT:    GIR_AddRegister, /*InsnID*/0, MyTarget::R0,
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/1, // src1
-// CHECK-NEXT:    GIR_MergeMemOperands, /*InsnID*/0, /*MergeInsnID's*/0, GIU_MergeMemOperands_EndOfList,
 // CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
@@ -569,7 +559,6 @@ def XORManyDefaults : I<(outs GPR32:$dst), (ins m1Z:$src3, Z:$src2, GPR32:$src1)
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/0, // dst
 // CHECK-NEXT:    GIR_AddRegister, /*InsnID*/0, MyTarget::R0,
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/1, // Wm
-// CHECK-NEXT:    GIR_MergeMemOperands, /*InsnID*/0, /*MergeInsnID's*/0, GIU_MergeMemOperands_EndOfList,
 // CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
@@ -612,7 +601,6 @@ def : Pat<(i32 (bitconvert FPR32:$src1)),
 // CHECK-NEXT:    // 1:i32  =>  (MOV1:i32)
 // CHECK-NEXT:    GIR_BuildMI, /*InsnID*/0, /*Opcode*/MyTarget::MOV1,
 // CHECK-NEXT:    GIR_Copy, /*NewInsnID*/0, /*OldInsnID*/0, /*OpIdx*/0, // dst
-// CHECK-NEXT:    GIR_MergeMemOperands, /*InsnID*/0, /*MergeInsnID's*/0, GIU_MergeMemOperands_EndOfList,
 // CHECK-NEXT:    GIR_EraseFromParent, /*InsnID*/0,
 // CHECK-NEXT:    GIR_ConstrainSelectedInstOperands, /*InsnID*/0,
 // CHECK-NEXT:    GIR_Done,
diff --git a/llvm/utils/TableGen/GlobalISelEmitter.cpp b/llvm/utils/TableGen/GlobalISelEmitter.cpp
index 13303ebc2b1..cac40a764ec 100644
--- a/llvm/utils/TableGen/GlobalISelEmitter.cpp
+++ b/llvm/utils/TableGen/GlobalISelEmitter.cpp
@@ -1462,24 +1462,27 @@ public:
     for (const auto &Renderer : OperandRenderers)
       Renderer->emitRenderOpcodes(Table, Rule);
 
-    Table << MatchTable::Opcode("GIR_MergeMemOperands")
-          << MatchTable::Comment("InsnID") << MatchTable::IntValue(InsnID)
-          << MatchTable::Comment("MergeInsnID's");
-    // Emit the ID's for all the instructions that are matched by this rule.
-    // TODO: Limit this to matched instructions that mayLoad/mayStore or have
-    //       some other means of having a memoperand. Also limit this to emitted
-    //       instructions that expect to have a memoperand too. For example,
-    //       (G_SEXT (G_LOAD x)) that results in separate load and sign-extend
-    //       instructions shouldn't put the memoperand on the sign-extend since
-    //       it has no effect there.
-    std::vector<unsigned> MergeInsnIDs;
-    for (const auto &IDMatcherPair : Rule.defined_insn_vars())
-      MergeInsnIDs.push_back(IDMatcherPair.second);
-    std::sort(MergeInsnIDs.begin(), MergeInsnIDs.end());
-    for (const auto &MergeInsnID : MergeInsnIDs)
-      Table << MatchTable::IntValue(MergeInsnID);
-    Table << MatchTable::NamedValue("GIU_MergeMemOperands_EndOfList")
-          << MatchTable::LineBreak << MatchTable::Opcode("GIR_EraseFromParent")
+    if (I->mayLoad || I->mayStore) {
+      Table << MatchTable::Opcode("GIR_MergeMemOperands")
+            << MatchTable::Comment("InsnID") << MatchTable::IntValue(InsnID)
+            << MatchTable::Comment("MergeInsnID's");
+      // Emit the ID's for all the instructions that are matched by this rule.
+      // TODO: Limit this to matched instructions that mayLoad/mayStore or have
+      //       some other means of having a memoperand. Also limit this to
+      //       emitted instructions that expect to have a memoperand too. For
+      //       example, (G_SEXT (G_LOAD x)) that results in separate load and
+      //       sign-extend instructions shouldn't put the memoperand on the
+      //       sign-extend since it has no effect there.
+      std::vector<unsigned> MergeInsnIDs;
+      for (const auto &IDMatcherPair : Rule.defined_insn_vars())
+        MergeInsnIDs.push_back(IDMatcherPair.second);
+      std::sort(MergeInsnIDs.begin(), MergeInsnIDs.end());
+      for (const auto &MergeInsnID : MergeInsnIDs)
+        Table << MatchTable::IntValue(MergeInsnID);
+      Table << MatchTable::NamedValue("GIU_MergeMemOperands_EndOfList");
+    }
+
+    Table << MatchTable::Opcode("GIR_EraseFromParent")
           << MatchTable::Comment("InsnID")
           << MatchTable::IntValue(RecycleInsnID) << MatchTable::LineBreak;
   }