[X86] X86DAGToDAGISel::matchBitExtract(): pattern b: truncation awareness

Summary:
(Not so) boringly identical to pattern a (D62786)
Not yet sure how do deal with the last pattern c.

Reviewers: RKSimon, craig.topper, spatel

Reviewed By: RKSimon

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62793

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@364418 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/CodeGen/SelectionDAG.h b/include/llvm/CodeGen/SelectionDAG.h
index 070c644..e640dd6 100644 (file)
--- a/include/llvm/CodeGen/SelectionDAG.h
+++ b/include/llvm/CodeGen/SelectionDAG.h
@@ -1468,6 +1468,11 @@ public:
   bool MaskedValueIsZero(SDValue Op, const APInt &Mask,
                          const APInt &DemandedElts, unsigned Depth = 0) const;
 
+  /// Return true if '(Op & Mask) == Mask'.
+  /// Op and Mask are known to be the same type.
+  bool MaskedValueIsAllOnes(SDValue Op, const APInt &Mask,
+                            unsigned Depth = 0) const;
+
   /// Determine which bits of Op are known to be either zero or one and return
   /// them in Known. For vectors, the known bits are those that are shared by
   /// every vector element.

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index a2eca91..a69fe1d 100644 (file)
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -2244,6 +2244,12 @@ bool SelectionDAG::MaskedValueIsZero(SDValue V, const APInt &Mask,
   return Mask.isSubsetOf(computeKnownBits(V, DemandedElts, Depth).Zero);
 }
 
+/// MaskedValueIsAllOnes - Return true if '(Op & Mask) == Mask'.
+bool SelectionDAG::MaskedValueIsAllOnes(SDValue V, const APInt &Mask,
+                                        unsigned Depth) const {
+  return Mask.isSubsetOf(computeKnownBits(V, Depth).One);
+}
+
 /// isSplatValue - Return true if the vector V has the same value
 /// across all DemandedElts.
 bool SelectionDAG::isSplatValue(SDValue V, const APInt &DemandedElts,

diff --git a/lib/Target/X86/X86ISelDAGToDAG.cpp b/lib/Target/X86/X86ISelDAGToDAG.cpp
index 537a689..36f71d0 100644 (file)
--- a/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -3179,16 +3179,28 @@ bool X86DAGToDAGISel::matchBitExtract(SDNode *Node) {
     return true;
   };
 
+  auto isAllOnes = [this, peekThroughOneUseTruncation, NVT](SDValue V) {
+    V = peekThroughOneUseTruncation(V);
+    return CurDAG->MaskedValueIsAllOnes(
+        V, APInt::getLowBitsSet(V.getSimpleValueType().getSizeInBits(),
+                                NVT.getSizeInBits()));
+  };
+
   // b) x & ~(-1 << nbits)
-  auto matchPatternB = [&checkOneUse, &NBits](SDValue Mask) -> bool {
+  auto matchPatternB = [&checkOneUse, isAllOnes, &peekThroughOneUseTruncation,
+                        &NBits](SDValue Mask) -> bool {
     // Match `~()`. Must only have one use!
-    if (!isBitwiseNot(Mask) || !checkOneUse(Mask))
+    if (Mask.getOpcode() != ISD::XOR || !checkOneUse(Mask))
       return false;
-    // Match `-1 << nbits`. Must only have one use!
-    SDValue M0 = Mask->getOperand(0);
+    // The -1 only has to be all-ones for the final Node's NVT.
+    if (!isAllOnes(Mask->getOperand(1)))
+      return false;
+    // Match `-1 << nbits`. Might be truncated. Must only have one use!
+    SDValue M0 = peekThroughOneUseTruncation(Mask->getOperand(0));
     if (M0->getOpcode() != ISD::SHL || !checkOneUse(M0))
       return false;
-    if (!isAllOnesConstant(M0->getOperand(0)))
+    // The -1 only has to be all-ones for the final Node's NVT.
+    if (!isAllOnes(M0->getOperand(0)))
       return false;
     NBits = M0->getOperand(1);
     return true;

diff --git a/test/CodeGen/X86/extract-bits.ll b/test/CodeGen/X86/extract-bits.ll
index c5c64b0..6d0553a 100644 (file)
--- a/test/CodeGen/X86/extract-bits.ll
+++ b/test/CodeGen/X86/extract-bits.ll
@@ -3667,22 +3667,17 @@ define i32 @bextr64_32_b0(i64 %val, i64 %numskipbits, i8 %numlowbits) nounwind {
 ;
 ; X64-BMI1NOTBM-LABEL: bextr64_32_b0:
 ; X64-BMI1NOTBM:       # %bb.0:
-; X64-BMI1NOTBM-NEXT:    movq %rsi, %rcx
-; X64-BMI1NOTBM-NEXT:    # kill: def $cl killed $cl killed $rcx
-; X64-BMI1NOTBM-NEXT:    shrq %cl, %rdi
-; X64-BMI1NOTBM-NEXT:    movq $-1, %rax
-; X64-BMI1NOTBM-NEXT:    movl %edx, %ecx
-; X64-BMI1NOTBM-NEXT:    shlq %cl, %rax
-; X64-BMI1NOTBM-NEXT:    andnl %edi, %eax, %eax
+; X64-BMI1NOTBM-NEXT:    shll $8, %edx
+; X64-BMI1NOTBM-NEXT:    movzbl %sil, %eax
+; X64-BMI1NOTBM-NEXT:    orl %edx, %eax
+; X64-BMI1NOTBM-NEXT:    bextrq %rax, %rdi, %rax
+; X64-BMI1NOTBM-NEXT:    # kill: def $eax killed $eax killed $rax
 ; X64-BMI1NOTBM-NEXT:    retq
 ;
 ; X64-BMI1BMI2-LABEL: bextr64_32_b0:
 ; X64-BMI1BMI2:       # %bb.0:
-; X64-BMI1BMI2-NEXT:    # kill: def $edx killed $edx def $rdx
 ; X64-BMI1BMI2-NEXT:    shrxq %rsi, %rdi, %rax
-; X64-BMI1BMI2-NEXT:    movq $-1, %rcx
-; X64-BMI1BMI2-NEXT:    shlxq %rdx, %rcx, %rcx
-; X64-BMI1BMI2-NEXT:    andnl %eax, %ecx, %eax
+; X64-BMI1BMI2-NEXT:    bzhil %edx, %eax, %eax
 ; X64-BMI1BMI2-NEXT:    retq
   %shiftedval = lshr i64 %val, %numskipbits
   %widenumlowbits = zext i8 %numlowbits to i64
@@ -4001,27 +3996,17 @@ define i32 @bextr64_32_b3(i64 %val, i64 %numskipbits, i8 %numlowbits) nounwind {
 ;
 ; X64-BMI1NOTBM-LABEL: bextr64_32_b3:
 ; X64-BMI1NOTBM:       # %bb.0:
-; X64-BMI1NOTBM-NEXT:    movq %rsi, %rcx
-; X64-BMI1NOTBM-NEXT:    # kill: def $cl killed $cl killed $rcx
-; X64-BMI1NOTBM-NEXT:    shrq %cl, %rdi
-; X64-BMI1NOTBM-NEXT:    movl $4294967295, %eax # imm = 0xFFFFFFFF
-; X64-BMI1NOTBM-NEXT:    movl $4294967295, %esi # imm = 0xFFFFFFFF
-; X64-BMI1NOTBM-NEXT:    movl %edx, %ecx
-; X64-BMI1NOTBM-NEXT:    shlq %cl, %rsi
-; X64-BMI1NOTBM-NEXT:    xorl %esi, %eax
-; X64-BMI1NOTBM-NEXT:    andl %edi, %eax
+; X64-BMI1NOTBM-NEXT:    shll $8, %edx
+; X64-BMI1NOTBM-NEXT:    movzbl %sil, %eax
+; X64-BMI1NOTBM-NEXT:    orl %edx, %eax
+; X64-BMI1NOTBM-NEXT:    bextrq %rax, %rdi, %rax
 ; X64-BMI1NOTBM-NEXT:    # kill: def $eax killed $eax killed $rax
 ; X64-BMI1NOTBM-NEXT:    retq
 ;
 ; X64-BMI1BMI2-LABEL: bextr64_32_b3:
 ; X64-BMI1BMI2:       # %bb.0:
-; X64-BMI1BMI2-NEXT:    # kill: def $edx killed $edx def $rdx
 ; X64-BMI1BMI2-NEXT:    shrxq %rsi, %rdi, %rax
-; X64-BMI1BMI2-NEXT:    movl $4294967295, %ecx # imm = 0xFFFFFFFF
-; X64-BMI1BMI2-NEXT:    shlxq %rdx, %rcx, %rdx
-; X64-BMI1BMI2-NEXT:    xorl %edx, %ecx
-; X64-BMI1BMI2-NEXT:    andl %ecx, %eax
-; X64-BMI1BMI2-NEXT:    # kill: def $eax killed $eax killed $rax
+; X64-BMI1BMI2-NEXT:    bzhil %edx, %eax, %eax
 ; X64-BMI1BMI2-NEXT:    retq
   %shiftedval = lshr i64 %val, %numskipbits
   %widenumlowbits = zext i8 %numlowbits to i64

diff --git a/test/CodeGen/X86/extract-lowbits.ll b/test/CodeGen/X86/extract-lowbits.ll
index 727b444..f17074a 100644 (file)
--- a/test/CodeGen/X86/extract-lowbits.ll
+++ b/test/CodeGen/X86/extract-lowbits.ll
@@ -1845,19 +1845,13 @@ define i32 @bzhi64_32_b0(i64 %val, i8 %numlowbits) nounwind {
 ;
 ; X64-BMI1NOTBM-LABEL: bzhi64_32_b0:
 ; X64-BMI1NOTBM:       # %bb.0:
-; X64-BMI1NOTBM-NEXT:    movl %esi, %ecx
-; X64-BMI1NOTBM-NEXT:    movq $-1, %rax
-; X64-BMI1NOTBM-NEXT:    # kill: def $cl killed $cl killed $ecx
-; X64-BMI1NOTBM-NEXT:    shlq %cl, %rax
-; X64-BMI1NOTBM-NEXT:    andnl %edi, %eax, %eax
+; X64-BMI1NOTBM-NEXT:    shll $8, %esi
+; X64-BMI1NOTBM-NEXT:    bextrl %esi, %edi, %eax
 ; X64-BMI1NOTBM-NEXT:    retq
 ;
 ; X64-BMI1BMI2-LABEL: bzhi64_32_b0:
 ; X64-BMI1BMI2:       # %bb.0:
-; X64-BMI1BMI2-NEXT:    # kill: def $esi killed $esi def $rsi
-; X64-BMI1BMI2-NEXT:    movq $-1, %rax
-; X64-BMI1BMI2-NEXT:    shlxq %rsi, %rax, %rax
-; X64-BMI1BMI2-NEXT:    andnl %edi, %eax, %eax
+; X64-BMI1BMI2-NEXT:    bzhil %esi, %edi, %eax
 ; X64-BMI1BMI2-NEXT:    retq
   %widenumlowbits = zext i8 %numlowbits to i64
   %notmask = shl nsw i64 -1, %widenumlowbits
@@ -2032,24 +2026,13 @@ define i32 @bzhi64_32_b3(i64 %val, i8 %numlowbits) nounwind {
 ;
 ; X64-BMI1NOTBM-LABEL: bzhi64_32_b3:
 ; X64-BMI1NOTBM:       # %bb.0:
-; X64-BMI1NOTBM-NEXT:    movl %esi, %ecx
-; X64-BMI1NOTBM-NEXT:    movl $4294967295, %eax # imm = 0xFFFFFFFF
-; X64-BMI1NOTBM-NEXT:    movl $4294967295, %edx # imm = 0xFFFFFFFF
-; X64-BMI1NOTBM-NEXT:    # kill: def $cl killed $cl killed $ecx
-; X64-BMI1NOTBM-NEXT:    shlq %cl, %rdx
-; X64-BMI1NOTBM-NEXT:    xorl %edx, %eax
-; X64-BMI1NOTBM-NEXT:    andl %edi, %eax
-; X64-BMI1NOTBM-NEXT:    # kill: def $eax killed $eax killed $rax
+; X64-BMI1NOTBM-NEXT:    shll $8, %esi
+; X64-BMI1NOTBM-NEXT:    bextrl %esi, %edi, %eax
 ; X64-BMI1NOTBM-NEXT:    retq
 ;
 ; X64-BMI1BMI2-LABEL: bzhi64_32_b3:
 ; X64-BMI1BMI2:       # %bb.0:
-; X64-BMI1BMI2-NEXT:    # kill: def $esi killed $esi def $rsi
-; X64-BMI1BMI2-NEXT:    movl $4294967295, %eax # imm = 0xFFFFFFFF
-; X64-BMI1BMI2-NEXT:    shlxq %rsi, %rax, %rcx
-; X64-BMI1BMI2-NEXT:    xorl %ecx, %eax
-; X64-BMI1BMI2-NEXT:    andl %edi, %eax
-; X64-BMI1BMI2-NEXT:    # kill: def $eax killed $eax killed $rax
+; X64-BMI1BMI2-NEXT:    bzhil %esi, %edi, %eax
 ; X64-BMI1BMI2-NEXT:    retq
   %widenumlowbits = zext i8 %numlowbits to i64
   %notmask = shl nsw i64 4294967295, %widenumlowbits