[X86] Remove dead nodes left after ReplaceAllUsesWith calls during address matching

ReplaceAllUsesWith doesn't remove the node that was replaced. So its left around in the graph messing up use counts on other nodes.

One thing to note, is that this isn't valid if the node being deleted is the root node of an LEA match that gets rejected. In that case the node needs to stay alive because the isel table walking code would still have a reference to it that its going to try to match next. I don't think that's the case here though because the nodes being deleted here should be "and", "srl", and "zero_extend" none of which can be the root node of an LEA match.

Differential Revision: https://reviews.llvm.org/D61048

llvm-svn: 359121

3 files changed, 31 insertions, 26 deletions

diff --git a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
index fff6bb8571e..df7f1fc524b 100644
--- a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -1375,6 +1375,7 @@ static bool foldMaskAndShiftToExtract(SelectionDAG &DAG, SDValue N,
   insertDAGNode(DAG, N, ShlCount);
   insertDAGNode(DAG, N, Shl);
   DAG.ReplaceAllUsesWith(N, Shl);
+  DAG.RemoveDeadNode(N.getNode());
   AM.IndexReg = And;
   AM.Scale = (1 << ScaleLog);
   return false;
@@ -1441,6 +1442,7 @@ static bool foldMaskedShiftToScaledMask(SelectionDAG &DAG, SDValue N,
   insertDAGNode(DAG, N, NewAnd);
   insertDAGNode(DAG, N, NewShift);
   DAG.ReplaceAllUsesWith(N, NewShift);
+  DAG.RemoveDeadNode(N.getNode());
 
   AM.Scale = 1 << ShiftAmt;
   AM.IndexReg = NewAnd;
@@ -1551,6 +1553,7 @@ static bool foldMaskAndShiftToScale(SelectionDAG &DAG, SDValue N,
   insertDAGNode(DAG, N, NewSHLAmt);
   insertDAGNode(DAG, N, NewSHL);
   DAG.ReplaceAllUsesWith(N, NewSHL);
+  DAG.RemoveDeadNode(N.getNode());
 
   AM.Scale = 1 << AMShiftAmt;
   AM.IndexReg = NewSRL;
@@ -1609,6 +1612,7 @@ static bool foldMaskedShiftToBEXTR(SelectionDAG &DAG, SDValue N,
   insertDAGNode(DAG, N, NewSHLAmt);
   insertDAGNode(DAG, N, NewSHL);
   DAG.ReplaceAllUsesWith(N, NewSHL);
+  DAG.RemoveDeadNode(N.getNode());
 
   AM.Scale = 1 << AMShiftAmt;
   AM.IndexReg = NewAnd;
@@ -1940,6 +1944,7 @@ bool X86DAGToDAGISel::matchAddressRecursively(SDValue N, X86ISelAddressMode &AM,
     insertDAGNode(*CurDAG, N, Zext);
     insertDAGNode(*CurDAG, N, NewShl);
     CurDAG->ReplaceAllUsesWith(N, NewShl);
+    CurDAG->RemoveDeadNode(N.getNode());
     return false;
   }
   }
diff --git a/llvm/test/CodeGen/X86/fold-and-shift.ll b/llvm/test/CodeGen/X86/fold-and-shift.ll
index 39c91d90017..e14e337ea89 100644
--- a/llvm/test/CodeGen/X86/fold-and-shift.ll
+++ b/llvm/test/CodeGen/X86/fold-and-shift.ll
@@ -5,8 +5,8 @@ define i32 @t1(i8* %X, i32 %i) {
 ; CHECK-LABEL: t1:
 ; CHECK:       # %bb.0: # %entry
 ; CHECK-NEXT:    movl {{[0-9]+}}(%esp), %eax
-; CHECK-NEXT:    movl {{[0-9]+}}(%esp), %ecx
-; CHECK-NEXT:    movzbl %cl, %ecx
+; CHECK-NEXT:    movl $255, %ecx
+; CHECK-NEXT:    andl {{[0-9]+}}(%esp), %ecx
 ; CHECK-NEXT:    movl (%eax,%ecx,4), %eax
 ; CHECK-NEXT:    retl
 
@@ -23,8 +23,8 @@ define i32 @t2(i16* %X, i32 %i) {
 ; CHECK-LABEL: t2:
 ; CHECK:       # %bb.0: # %entry
 ; CHECK-NEXT:    movl {{[0-9]+}}(%esp), %eax
-; CHECK-NEXT:    movl {{[0-9]+}}(%esp), %ecx
-; CHECK-NEXT:    movzwl %cx, %ecx
+; CHECK-NEXT:    movl $65535, %ecx # imm = 0xFFFF
+; CHECK-NEXT:    andl {{[0-9]+}}(%esp), %ecx
 ; CHECK-NEXT:    movl (%eax,%ecx,4), %eax
 ; CHECK-NEXT:    retl
 
@@ -111,8 +111,8 @@ define i8 @t6(i8* %X, i32 %i) {
 ; CHECK-LABEL: t6:
 ; CHECK:       # %bb.0: # %entry
 ; CHECK-NEXT:    movl {{[0-9]+}}(%esp), %eax
-; CHECK-NEXT:    movl {{[0-9]+}}(%esp), %ecx
-; CHECK-NEXT:    andl $-255, %ecx
+; CHECK-NEXT:    movl $-255, %ecx
+; CHECK-NEXT:    andl {{[0-9]+}}(%esp), %ecx
 ; CHECK-NEXT:    movb (%eax,%ecx,4), %al
 ; CHECK-NEXT:    retl
 
diff --git a/llvm/test/CodeGen/X86/pr32329.ll b/llvm/test/CodeGen/X86/pr32329.ll
index 21109469723..8323bd1a242 100644
--- a/llvm/test/CodeGen/X86/pr32329.ll
+++ b/llvm/test/CodeGen/X86/pr32329.ll
@@ -29,18 +29,18 @@ define void @foo() local_unnamed_addr {
 ; X86-NEXT:    .cfi_offset %edi, -16
 ; X86-NEXT:    .cfi_offset %ebx, -12
 ; X86-NEXT:    .cfi_offset %ebp, -8
-; X86-NEXT:    movl obj, %edx
 ; X86-NEXT:    movsbl var_27, %eax
 ; X86-NEXT:    movzwl var_2, %esi
 ; X86-NEXT:    movl var_310, %ecx
 ; X86-NEXT:    imull %eax, %ecx
 ; X86-NEXT:    addl var_24, %ecx
-; X86-NEXT:    andl $4194303, %edx # imm = 0x3FFFFF
-; X86-NEXT:    leal (%edx,%edx), %ebx
-; X86-NEXT:    subl %eax, %ebx
-; X86-NEXT:    movl %ebx, %edi
-; X86-NEXT:    subl %esi, %edi
-; X86-NEXT:    imull %edi, %ecx
+; X86-NEXT:    movl $4194303, %edi # imm = 0x3FFFFF
+; X86-NEXT:    andl obj, %edi
+; X86-NEXT:    leal (%edi,%edi), %edx
+; X86-NEXT:    subl %eax, %edx
+; X86-NEXT:    movl %edx, %ebx
+; X86-NEXT:    subl %esi, %ebx
+; X86-NEXT:    imull %ebx, %ecx
 ; X86-NEXT:    addb $113, %cl
 ; X86-NEXT:    movl $9, %esi
 ; X86-NEXT:    xorl %ebp, %ebp
@@ -50,12 +50,12 @@ define void @foo() local_unnamed_addr {
 ; X86-NEXT:    cmovnel %esi, %ebp
 ; X86-NEXT:    movl $0, %ecx
 ; X86-NEXT:    cmovnel %ecx, %esi
-; X86-NEXT:    cmpl %edx, %edi
+; X86-NEXT:    cmpl %edi, %ebx
 ; X86-NEXT:    movl %ebp, var_50+4
 ; X86-NEXT:    movl %esi, var_50
 ; X86-NEXT:    setge var_205
-; X86-NEXT:    imull %eax, %ebx
-; X86-NEXT:    movb %bl, var_218
+; X86-NEXT:    imull %eax, %edx
+; X86-NEXT:    movb %dl, var_218
 ; X86-NEXT:    popl %esi
 ; X86-NEXT:    .cfi_def_cfa_offset 16
 ; X86-NEXT:    popl %edi
@@ -68,24 +68,24 @@ define void @foo() local_unnamed_addr {
 ;
 ; X64-LABEL: foo:
 ; X64:       # %bb.0: # %entry
-; X64-NEXT:    movl {{.*}}(%rip), %eax
 ; X64-NEXT:    movsbl {{.*}}(%rip), %r9d
 ; X64-NEXT:    movzwl {{.*}}(%rip), %r8d
 ; X64-NEXT:    movl {{.*}}(%rip), %ecx
 ; X64-NEXT:    imull %r9d, %ecx
 ; X64-NEXT:    addl {{.*}}(%rip), %ecx
-; X64-NEXT:    andl $4194303, %eax # imm = 0x3FFFFF
-; X64-NEXT:    leal (%rax,%rax), %edi
+; X64-NEXT:    movl $4194303, %esi # imm = 0x3FFFFF
+; X64-NEXT:    andl {{.*}}(%rip), %esi
+; X64-NEXT:    leal (%rsi,%rsi), %edi
 ; X64-NEXT:    subl %r9d, %edi
-; X64-NEXT:    movl %edi, %esi
-; X64-NEXT:    subl %r8d, %esi
-; X64-NEXT:    imull %esi, %ecx
+; X64-NEXT:    movl %edi, %edx
+; X64-NEXT:    subl %r8d, %edx
+; X64-NEXT:    imull %edx, %ecx
 ; X64-NEXT:    addb $113, %cl
-; X64-NEXT:    movl $9, %edx
+; X64-NEXT:    movl $9, %eax
 ; X64-NEXT:    # kill: def $cl killed $cl killed $ecx
-; X64-NEXT:    shlq %cl, %rdx
-; X64-NEXT:    movq %rdx, {{.*}}(%rip)
-; X64-NEXT:    cmpl %eax, %esi
+; X64-NEXT:    shlq %cl, %rax
+; X64-NEXT:    movq %rax, {{.*}}(%rip)
+; X64-NEXT:    cmpl %esi, %edx
 ; X64-NEXT:    setge {{.*}}(%rip)
 ; X64-NEXT:    imull %r9d, %edi
 ; X64-NEXT:    movb %dil, {{.*}}(%rip)