[llvm] r362681 - [AArch64][GlobalISel] Add manual selection support for G_ZEXTLOADs to s64.

Amara Emerson via llvm-commits llvm-commits at lists.llvm.org
Thu Jun 6 00:58:38 PDT 2019


Author: aemerson
Date: Thu Jun  6 00:58:37 2019
New Revision: 362681

URL: http://llvm.org/viewvc/llvm-project?rev=362681&view=rev
Log:
[AArch64][GlobalISel] Add manual selection support for G_ZEXTLOADs to s64.

We already get support for G_ZEXTLOAD to s32 from the importer, but it can't
deal with the SUBREG_TO_REG in the pattern. Tweaking the existing manual
selection code for G_LOAD to handle an additional SUBREG_TO_REG when dealing
with G_ZEXTLOAD isn't much work.

Also add tests to check the imported pattern selections to s32 work.

Modified:
    llvm/trunk/lib/Target/AArch64/AArch64InstructionSelector.cpp
    llvm/trunk/test/CodeGen/AArch64/GlobalISel/select-zextload.mir

Modified: llvm/trunk/lib/Target/AArch64/AArch64InstructionSelector.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AArch64/AArch64InstructionSelector.cpp?rev=362681&r1=362680&r2=362681&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64InstructionSelector.cpp (original)
+++ llvm/trunk/lib/Target/AArch64/AArch64InstructionSelector.cpp Thu Jun  6 00:58:37 2019
@@ -1392,8 +1392,12 @@ bool AArch64InstructionSelector::select(
     return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
   }
 
+  case TargetOpcode::G_ZEXTLOAD:
   case TargetOpcode::G_LOAD:
   case TargetOpcode::G_STORE: {
+    bool IsZExtLoad = I.getOpcode() == TargetOpcode::G_ZEXTLOAD;
+    MachineIRBuilder MIB(I);
+
     LLT PtrTy = MRI.getType(I.getOperand(1).getReg());
 
     if (PtrTy != LLT::pointer(0, 64)) {
@@ -1464,6 +1468,25 @@ bool AArch64InstructionSelector::select(
       }
     }
 
+    if (IsZExtLoad) {
+      // The zextload from a smaller type to i32 should be handled by the importer.
+      if (MRI.getType(ValReg).getSizeInBits() != 64)
+        return false;
+      // If we have a ZEXTLOAD then change the load's type to be a narrower reg
+      //and zero_extend with SUBREG_TO_REG.
+      unsigned LdReg = MRI.createVirtualRegister(&AArch64::GPR32RegClass);
+      unsigned DstReg = I.getOperand(0).getReg();
+      I.getOperand(0).setReg(LdReg);
+
+      MIB.setInsertPt(MIB.getMBB(), std::next(I.getIterator()));
+      MIB.buildInstr(AArch64::SUBREG_TO_REG, {DstReg}, {})
+          .addImm(0)
+          .addUse(LdReg)
+          .addImm(AArch64::sub_32);
+      constrainSelectedInstRegOperands(I, TII, TRI, RBI);
+      return RBI.constrainGenericRegister(DstReg, AArch64::GPR64allRegClass,
+                                          MRI);
+    }
     return constrainSelectedInstRegOperands(I, TII, TRI, RBI);
   }
 

Modified: llvm/trunk/test/CodeGen/AArch64/GlobalISel/select-zextload.mir
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AArch64/GlobalISel/select-zextload.mir?rev=362681&r1=362680&r2=362681&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/AArch64/GlobalISel/select-zextload.mir (original)
+++ llvm/trunk/test/CodeGen/AArch64/GlobalISel/select-zextload.mir Thu Jun  6 00:58:37 2019
@@ -6,6 +6,37 @@
 
   define void @zextload_s32_from_s16(i16 *%addr) { ret void }
   define void @zextload_s32_from_s16_not_combined(i16 *%addr) { ret void }
+
+  define i64 @i32_to_i64(i32* %ptr) {
+    %ld = load i32, i32* %ptr, align 4
+    %val = zext i32 %ld to i64
+    ret i64 %val
+  }
+
+  define i64 @i16_to_i64(i16* %ptr) {
+    %ld = load i16, i16* %ptr, align 2
+    %val = zext i16 %ld to i64
+    ret i64 %val
+  }
+
+  define i64 @i8_to_i64(i8* %ptr) {
+    %ld = load i8, i8* %ptr, align 1
+    %val = zext i8 %ld to i64
+    ret i64 %val
+  }
+
+  define i32 @i8_to_i32(i8* %ptr) {
+    %ld = load i8, i8* %ptr, align 1
+    %val = zext i8 %ld to i32
+    ret i32 %val
+  }
+
+  define i32 @i16_to_i32(i16* %ptr) {
+    %ld = load i16, i16* %ptr, align 2
+    %val = zext i16 %ld to i32
+    ret i32 %val
+  }
+
 ...
 
 ---
@@ -19,8 +50,8 @@ body:             |
 
     ; CHECK-LABEL: name: zextload_s32_from_s16
     ; CHECK: [[COPY:%[0-9]+]]:gpr64sp = COPY $x0
-    ; CHECK: [[T0:%[0-9]+]]:gpr32 = LDRHHui [[COPY]], 0 :: (load 2 from %ir.addr)
-    ; CHECK: $w0 = COPY [[T0]]
+    ; CHECK: [[LDRHHui:%[0-9]+]]:gpr32 = LDRHHui [[COPY]], 0 :: (load 2 from %ir.addr)
+    ; CHECK: $w0 = COPY [[LDRHHui]]
     %0:gpr(p0) = COPY $x0
     %1:gpr(s32) = G_ZEXTLOAD %0 :: (load 2 from %ir.addr)
     $w0 = COPY %1(s32)
@@ -36,11 +67,109 @@ body:             |
 
     ; CHECK-LABEL: name: zextload_s32_from_s16_not_combined
     ; CHECK: [[COPY:%[0-9]+]]:gpr64sp = COPY $x0
-    ; CHECK: [[T0:%[0-9]+]]:gpr32 = LDRHHui [[COPY]], 0 :: (load 2 from %ir.addr)
-    ; CHECK: [[T1:%[0-9]+]]:gpr32 = UBFMWri [[T0]], 0, 15
-    ; CHECK: $w0 = COPY [[T1]]
+    ; CHECK: [[LDRHHui:%[0-9]+]]:gpr32 = LDRHHui [[COPY]], 0 :: (load 2 from %ir.addr)
+    ; CHECK: [[UBFMWri:%[0-9]+]]:gpr32 = UBFMWri [[LDRHHui]], 0, 15
+    ; CHECK: $w0 = COPY [[UBFMWri]]
     %0:gpr(p0) = COPY $x0
     %1:gpr(s16) = G_LOAD %0 :: (load 2 from %ir.addr)
     %2:gpr(s32) = G_ZEXT %1
     $w0 = COPY %2(s32)
 ...
+---
+name:            i32_to_i64
+legalized:       true
+regBankSelected: true
+body:             |
+  bb.1 (%ir-block.0):
+    liveins: $x0
+
+    ; CHECK-LABEL: name: i32_to_i64
+    ; CHECK: [[COPY:%[0-9]+]]:gpr64sp = COPY $x0
+    ; CHECK: [[LDRWui:%[0-9]+]]:gpr32 = LDRWui [[COPY]], 0 :: (load 4 from %ir.ptr)
+    ; CHECK: [[SUBREG_TO_REG:%[0-9]+]]:gpr64all = SUBREG_TO_REG 0, [[LDRWui]], %subreg.sub_32
+    ; CHECK: $x0 = COPY [[SUBREG_TO_REG]]
+    ; CHECK: RET_ReallyLR implicit $x0
+    %0:gpr(p0) = COPY $x0
+    %2:gpr(s64) = G_ZEXTLOAD %0(p0) :: (load 4 from %ir.ptr)
+    $x0 = COPY %2(s64)
+    RET_ReallyLR implicit $x0
+
+...
+---
+name:            i16_to_i64
+legalized:       true
+regBankSelected: true
+body:             |
+  bb.1 (%ir-block.0):
+    liveins: $x0
+
+    ; CHECK-LABEL: name: i16_to_i64
+    ; CHECK: [[COPY:%[0-9]+]]:gpr64sp = COPY $x0
+    ; CHECK: [[LDRHHui:%[0-9]+]]:gpr32 = LDRHHui [[COPY]], 0 :: (load 2 from %ir.ptr)
+    ; CHECK: [[SUBREG_TO_REG:%[0-9]+]]:gpr64all = SUBREG_TO_REG 0, [[LDRHHui]], %subreg.sub_32
+    ; CHECK: $x0 = COPY [[SUBREG_TO_REG]]
+    ; CHECK: RET_ReallyLR implicit $x0
+    %0:gpr(p0) = COPY $x0
+    %2:gpr(s64) = G_ZEXTLOAD %0(p0) :: (load 2 from %ir.ptr)
+    $x0 = COPY %2(s64)
+    RET_ReallyLR implicit $x0
+
+...
+---
+name:            i8_to_i64
+legalized:       true
+regBankSelected: true
+body:             |
+  bb.1 (%ir-block.0):
+    liveins: $x0
+
+    ; CHECK-LABEL: name: i8_to_i64
+    ; CHECK: [[COPY:%[0-9]+]]:gpr64sp = COPY $x0
+    ; CHECK: [[LDRBBui:%[0-9]+]]:gpr32 = LDRBBui [[COPY]], 0 :: (load 1 from %ir.ptr)
+    ; CHECK: [[SUBREG_TO_REG:%[0-9]+]]:gpr64all = SUBREG_TO_REG 0, [[LDRBBui]], %subreg.sub_32
+    ; CHECK: $x0 = COPY [[SUBREG_TO_REG]]
+    ; CHECK: RET_ReallyLR implicit $x0
+    %0:gpr(p0) = COPY $x0
+    %2:gpr(s64) = G_ZEXTLOAD %0(p0) :: (load 1 from %ir.ptr)
+    $x0 = COPY %2(s64)
+    RET_ReallyLR implicit $x0
+
+...
+---
+name:            i8_to_i32
+legalized:       true
+regBankSelected: true
+body:             |
+  bb.1 (%ir-block.0):
+    liveins: $x0
+
+    ; CHECK-LABEL: name: i8_to_i32
+    ; CHECK: [[COPY:%[0-9]+]]:gpr64sp = COPY $x0
+    ; CHECK: [[LDRBBui:%[0-9]+]]:gpr32 = LDRBBui [[COPY]], 0 :: (load 1 from %ir.ptr)
+    ; CHECK: $w0 = COPY [[LDRBBui]]
+    ; CHECK: RET_ReallyLR implicit $w0
+    %0:gpr(p0) = COPY $x0
+    %2:gpr(s32) = G_ZEXTLOAD %0(p0) :: (load 1 from %ir.ptr)
+    $w0 = COPY %2(s32)
+    RET_ReallyLR implicit $w0
+
+...
+---
+name:            i16_to_i32
+legalized:       true
+regBankSelected: true
+body:             |
+  bb.1 (%ir-block.0):
+    liveins: $x0
+
+    ; CHECK-LABEL: name: i16_to_i32
+    ; CHECK: [[COPY:%[0-9]+]]:gpr64sp = COPY $x0
+    ; CHECK: [[LDRHHui:%[0-9]+]]:gpr32 = LDRHHui [[COPY]], 0 :: (load 2 from %ir.ptr)
+    ; CHECK: $w0 = COPY [[LDRHHui]]
+    ; CHECK: RET_ReallyLR implicit $w0
+    %0:gpr(p0) = COPY $x0
+    %2:gpr(s32) = G_ZEXTLOAD %0(p0) :: (load 2 from %ir.ptr)
+    $w0 = COPY %2(s32)
+    RET_ReallyLR implicit $w0
+
+...




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