[llvm] r189742 - Create BEXTR instructions for (and ((sra or srl) x, imm), (2**size - 1)). Fixes PR17028.

Craig Topper craig.topper at gmail.com
Mon Sep 2 00:53:17 PDT 2013


Author: ctopper
Date: Mon Sep  2 02:53:17 2013
New Revision: 189742

URL: http://llvm.org/viewvc/llvm-project?rev=189742&view=rev
Log:
Create BEXTR instructions for (and ((sra or srl) x, imm), (2**size - 1)). Fixes PR17028.

Modified:
    llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
    llvm/trunk/lib/Target/X86/X86ISelLowering.h
    llvm/trunk/lib/Target/X86/X86InstrInfo.td
    llvm/trunk/test/CodeGen/X86/bmi.ll

Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=189742&r1=189741&r2=189742&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Mon Sep  2 02:53:17 2013
@@ -13693,6 +13693,7 @@ const char *X86TargetLowering::getTarget
   case X86ISD::BLSMSK:             return "X86ISD::BLSMSK";
   case X86ISD::BLSR:               return "X86ISD::BLSR";
   case X86ISD::BZHI:               return "X86ISD::BZHI";
+  case X86ISD::BEXTR:              return "X86ISD::BEXTR";
   case X86ISD::MUL_IMM:            return "X86ISD::MUL_IMM";
   case X86ISD::PTEST:              return "X86ISD::PTEST";
   case X86ISD::TESTP:              return "X86ISD::TESTP";
@@ -17503,6 +17504,7 @@ static SDValue PerformAndCombine(SDNode
   // BLSI is X & (-X)
   // BLSR is X & (X-1)
   // BZHI is X & ((1 << Y) - 1)
+  // BEXTR is ((X >> imm) & (2**size-1))
   if (VT == MVT::i32 || VT == MVT::i64) {
     SDValue N0 = N->getOperand(0);
     SDValue N1 = N->getOperand(1);
@@ -17528,6 +17530,22 @@ static SDValue PerformAndCombine(SDNode
       if (N1.getOpcode() == ISD::ADD && N1.getOperand(0) == N0 &&
           isAllOnes(N1.getOperand(1)))
         return DAG.getNode(X86ISD::BLSR, DL, VT, N0);
+
+      // Check for BEXTR
+      if (N0.getOpcode() == ISD::SRA || N0.getOpcode() == ISD::SRL) {
+        ConstantSDNode *MaskNode = dyn_cast<ConstantSDNode>(N1);
+        ConstantSDNode *ShiftNode = dyn_cast<ConstantSDNode>(N0.getOperand(1));
+        if (MaskNode && ShiftNode) {
+          uint64_t Mask = MaskNode->getZExtValue();
+          uint64_t Shift = ShiftNode->getZExtValue();
+          if (isMask_64(Mask)) {
+            uint64_t MaskSize = CountPopulation_64(Mask);
+            if (Shift + MaskSize <= VT.getSizeInBits())
+              return DAG.getNode(X86ISD::BEXTR, DL, VT, N0.getOperand(0),
+                                 DAG.getConstant(Shift | (MaskSize << 8), VT));
+          }
+        }
+      }
     }
 
     if (Subtarget->hasBMI2()) {

Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.h?rev=189742&r1=189741&r2=189742&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.h (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.h Mon Sep  2 02:53:17 2013
@@ -296,6 +296,7 @@ namespace llvm {
       BLSMSK, // BLSMSK - Get mask up to lowest set bit
       BLSR,   // BLSR - Reset lowest set bit
       BZHI,   // BZHI - Zero high bits
+      BEXTR,  // BEXTR - Bit field extract
 
       UMUL, // LOW, HI, FLAGS = umul LHS, RHS
 

Modified: llvm/trunk/lib/Target/X86/X86InstrInfo.td
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86InstrInfo.td?rev=189742&r1=189741&r2=189742&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86InstrInfo.td (original)
+++ llvm/trunk/lib/Target/X86/X86InstrInfo.td Mon Sep  2 02:53:17 2013
@@ -253,6 +253,7 @@ def X86blsi   : SDNode<"X86ISD::BLSI",
 def X86blsmsk : SDNode<"X86ISD::BLSMSK", SDTIntUnaryOp>;
 def X86blsr   : SDNode<"X86ISD::BLSR",   SDTIntUnaryOp>;
 def X86bzhi   : SDNode<"X86ISD::BZHI",   SDTIntShiftOp>;
+def X86bextr  : SDNode<"X86ISD::BEXTR",  SDTIntShiftOp>;
 
 def X86mul_imm : SDNode<"X86ISD::MUL_IMM", SDTIntBinOp>;
 
@@ -1869,6 +1870,15 @@ def : Pat<(X86bzhi (loadi64 addr:$src1),
           (BZHI64rm addr:$src1,
                     (INSERT_SUBREG (i64 (IMPLICIT_DEF)), GR8:$src2, sub_8bit))>;
 
+def : Pat<(X86bextr GR32:$src1, GR32:$src2),
+          (BEXTR32rr GR32:$src1, GR32:$src2)>;
+def : Pat<(X86bextr (loadi32 addr:$src1), GR32:$src2),
+          (BEXTR32rm addr:$src1, GR32:$src2)>;
+def : Pat<(X86bextr GR64:$src1, GR64:$src2),
+          (BEXTR64rr GR64:$src1, GR64:$src2)>;
+def : Pat<(X86bextr (loadi64 addr:$src1), GR64:$src2),
+          (BEXTR64rm addr:$src1, GR64:$src2)>;
+
 multiclass bmi_pdep_pext<string mnemonic, RegisterClass RC,
                          X86MemOperand x86memop, Intrinsic Int,
                          PatFrag ld_frag> {

Modified: llvm/trunk/test/CodeGen/X86/bmi.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/bmi.ll?rev=189742&r1=189741&r2=189742&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/bmi.ll (original)
+++ llvm/trunk/test/CodeGen/X86/bmi.ll Mon Sep  2 02:53:17 2013
@@ -111,6 +111,23 @@ define i32 @bextr32_load(i32* %x, i32 %y
 
 declare i32 @llvm.x86.bmi.bextr.32(i32, i32) nounwind readnone
 
+define i32 @bextr32b(i32 %x) nounwind uwtable readnone ssp {
+  %1 = lshr i32 %x, 4
+  %2 = and i32 %1, 4095
+  ret i32 %2
+; CHECK-LABEL: bextr32b:
+; CHECK: bextrl
+}
+
+define i32 @bextr32b_load(i32* %x) nounwind uwtable readnone ssp {
+  %1 = load i32* %x
+  %2 = lshr i32 %1, 4
+  %3 = and i32 %2, 4095
+  ret i32 %3
+; CHECK-LABEL: bextr32b_load:
+; CHECK: bextrl {{.*}}, ({{.*}}), {{.*}}
+}
+
 define i64 @bextr64(i64 %x, i64 %y) nounwind readnone {
   %tmp = tail call i64 @llvm.x86.bmi.bextr.64(i64 %x, i64 %y)
   ret i64 %tmp
@@ -120,6 +137,14 @@ define i64 @bextr64(i64 %x, i64 %y) noun
 
 declare i64 @llvm.x86.bmi.bextr.64(i64, i64) nounwind readnone
 
+define i64 @bextr64b(i64 %x) nounwind uwtable readnone ssp {
+  %1 = lshr i64 %x, 4
+  %2 = and i64 %1, 4095
+  ret i64 %2
+; CHECK-LABEL: bextr64b:
+; CHECK: bextrq
+}
+
 define i32 @bzhi32(i32 %x, i32 %y) nounwind readnone {
   %tmp = tail call i32 @llvm.x86.bmi.bzhi.32(i32 %x, i32 %y)
   ret i32 %tmp





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