RegAllocGreedy: Check if copied lanes are live in trySplitAroundHintReg (#160424)

arsenm · web-flow · commit 3537e8abfa06 · 2025-10-02T12:21:02.000Z
For subregister copies, do a subregister live check instead of checking
the main range. Doesn't do much yet, the split analysis still does not
track live ranges.
diff --git a/llvm/lib/CodeGen/RegAllocGreedy.cpp b/llvm/lib/CodeGen/RegAllocGreedy.cpp
@@ -1406,8 +1406,24 @@ bool RAGreedy::trySplitAroundHintReg(MCPhysReg Hint,
       continue;
 
     // Check if VirtReg interferes with OtherReg after this COPY instruction.
-    if (!IsDef && VirtReg.liveAt(LIS->getInstructionIndex(Instr).getRegSlot()))
-      continue;
+    if (Opnd.readsReg()) {
+      SlotIndex Index = LIS->getInstructionIndex(Instr).getRegSlot();
+
+      if (SubReg) {
+        LaneBitmask Mask = TRI->getSubRegIndexLaneMask(SubReg);
+        if (IsDef)
+          Mask = ~Mask;
+
+        if (any_of(VirtReg.subranges(), [=](const LiveInterval::SubRange &S) {
+              return (S.LaneMask & Mask).any() && S.liveAt(Index);
+            })) {
+          continue;
+        }
+      } else {
+        if (VirtReg.liveAt(Index))
+          continue;
+      }
+    }
 
     MCRegister OtherPhysReg =
         OtherReg.isPhysical() ? OtherReg.asMCReg() : VRM->getPhys(OtherReg);
diff --git a/llvm/test/CodeGen/SystemZ/fp-cmp-04.ll b/llvm/test/CodeGen/SystemZ/fp-cmp-04.ll
@@ -235,7 +235,7 @@ define half @f12_half(half %dummy, half %val, ptr %dest) {
 ; CHECK-NEXT: blah %f0
 ; CHECK-NEXT: #NO_APP
 ; CHECK-NEXT: brasl %r14, __extendhfsf2@PLT
-; CHECK-NEXT: ltebr %f0, %f0
+; CHECK-NEXT: ltebr %f1, %f0
 ; CHECK-NEXT: jl .LBB11_2
 ; CHECK-NEXT:# %bb.1:
 ; CHECK-NEXT: lgdr %r0, %f8
@@ -344,7 +344,7 @@ define half @f15_half(half %val, half %dummy, ptr %dest) {
 ; CHECK-NEXT: blah %f2
 ; CHECK-NEXT: #NO_APP
 ; CHECK-NEXT: brasl %r14, __extendhfsf2@PLT
-; CHECK-NEXT: ltebr %f0, %f0
+; CHECK-NEXT: ltebr %f1, %f0
 ; CHECK-NEXT: jl .LBB15_2
 ; CHECK-NEXT:# %bb.1:
 ; CHECK-NEXT: lgdr %r0, %f8
diff --git a/llvm/test/CodeGen/X86/fshl.ll b/llvm/test/CodeGen/X86/fshl.ll
@@ -335,84 +335,83 @@ define i128 @var_shift_i128(i128 %x, i128 %y, i128 %z) nounwind {
 ; X86-SLOW-NEXT:    pushl %esi
 ; X86-SLOW-NEXT:    andl $-16, %esp
 ; X86-SLOW-NEXT:    subl $32, %esp
-; X86-SLOW-NEXT:    movl 24(%ebp), %esi
+; X86-SLOW-NEXT:    movl 24(%ebp), %edi
 ; X86-SLOW-NEXT:    movl 28(%ebp), %eax
 ; X86-SLOW-NEXT:    movl 48(%ebp), %edx
 ; X86-SLOW-NEXT:    movl 56(%ebp), %ecx
 ; X86-SLOW-NEXT:    testb $64, %cl
-; X86-SLOW-NEXT:    movl 52(%ebp), %edi
+; X86-SLOW-NEXT:    movl 52(%ebp), %ebx
 ; X86-SLOW-NEXT:    jne .LBB6_1
 ; X86-SLOW-NEXT:  # %bb.2:
 ; X86-SLOW-NEXT:    movl %edx, {{[-0-9]+}}(%e{{[sb]}}p) # 4-byte Spill
-; X86-SLOW-NEXT:    movl %esi, %edx
-; X86-SLOW-NEXT:    movl 32(%ebp), %esi
-; X86-SLOW-NEXT:    movl %edi, %ecx
-; X86-SLOW-NEXT:    movl %eax, %edi
+; X86-SLOW-NEXT:    movl %edi, %edx
+; X86-SLOW-NEXT:    movl 32(%ebp), %edi
+; X86-SLOW-NEXT:    movl %ebx, {{[-0-9]+}}(%e{{[sb]}}p) # 4-byte Spill
+; X86-SLOW-NEXT:    movl %eax, %ebx
 ; X86-SLOW-NEXT:    movl 36(%ebp), %eax
 ; X86-SLOW-NEXT:    jmp .LBB6_3
 ; X86-SLOW-NEXT:  .LBB6_1:
 ; X86-SLOW-NEXT:    movl 40(%ebp), %ecx
 ; X86-SLOW-NEXT:    movl %ecx, {{[-0-9]+}}(%e{{[sb]}}p) # 4-byte Spill
 ; X86-SLOW-NEXT:    movl 44(%ebp), %ecx
+; X86-SLOW-NEXT:    movl %ecx, {{[-0-9]+}}(%e{{[sb]}}p) # 4-byte Spill
 ; X86-SLOW-NEXT:  .LBB6_3:
-; X86-SLOW-NEXT:    movl 56(%ebp), %ebx
-; X86-SLOW-NEXT:    testb $32, %bl
+; X86-SLOW-NEXT:    movl 56(%ebp), %ecx
+; X86-SLOW-NEXT:    testb $32, %cl
 ; X86-SLOW-NEXT:    jne .LBB6_4
 ; X86-SLOW-NEXT:  # %bb.5:
-; X86-SLOW-NEXT:    movl %ecx, %ebx
 ; X86-SLOW-NEXT:    movl %edi, {{[-0-9]+}}(%e{{[sb]}}p) # 4-byte Spill
-; X86-SLOW-NEXT:    movl %esi, {{[-0-9]+}}(%e{{[sb]}}p) # 4-byte Spill
+; X86-SLOW-NEXT:    movl %edx, %edi
+; X86-SLOW-NEXT:    movl {{[-0-9]+}}(%e{{[sb]}}p), %esi # 4-byte Reload
 ; X86-SLOW-NEXT:    movl %eax, {{[-0-9]+}}(%e{{[sb]}}p) # 4-byte Spill
 ; X86-SLOW-NEXT:    jmp .LBB6_6
 ; X86-SLOW-NEXT:  .LBB6_4:
-; X86-SLOW-NEXT:    movl %esi, {{[-0-9]+}}(%e{{[sb]}}p) # 4-byte Spill
 ; X86-SLOW-NEXT:    movl %edi, {{[-0-9]+}}(%e{{[sb]}}p) # 4-byte Spill
-; X86-SLOW-NEXT:    movl %edx, {{[-0-9]+}}(%e{{[sb]}}p) # 4-byte Spill
-; X86-SLOW-NEXT:    movl %ecx, %edx
-; X86-SLOW-NEXT:    movl {{[-0-9]+}}(%e{{[sb]}}p), %ebx # 4-byte Reload
+; X86-SLOW-NEXT:    movl %ebx, {{[-0-9]+}}(%e{{[sb]}}p) # 4-byte Spill
+; X86-SLOW-NEXT:    movl %edx, %ebx
+; X86-SLOW-NEXT:    movl {{[-0-9]+}}(%e{{[sb]}}p), %edi # 4-byte Reload
+; X86-SLOW-NEXT:    movl {{[-0-9]+}}(%e{{[sb]}}p), %esi # 4-byte Reload
 ; X86-SLOW-NEXT:  .LBB6_6:
-; X86-SLOW-NEXT:    movl %edx, %esi
+; X86-SLOW-NEXT:    movl %edi, %eax
+; X86-SLOW-NEXT:    shll %cl, %eax
+; X86-SLOW-NEXT:    shrl %esi
+; X86-SLOW-NEXT:    movl %ecx, %edx
+; X86-SLOW-NEXT:    notb %dl
+; X86-SLOW-NEXT:    movl %edx, %ecx
+; X86-SLOW-NEXT:    shrl %cl, %esi
+; X86-SLOW-NEXT:    orl %eax, %esi
+; X86-SLOW-NEXT:    movl %esi, {{[-0-9]+}}(%e{{[sb]}}p) # 4-byte Spill
+; X86-SLOW-NEXT:    movl %ebx, %eax
 ; X86-SLOW-NEXT:    movl 56(%ebp), %ecx
-; X86-SLOW-NEXT:    shll %cl, %esi
-; X86-SLOW-NEXT:    movl %ebx, %edi
+; X86-SLOW-NEXT:    # kill: def $cl killed $cl killed $ecx
+; X86-SLOW-NEXT:    shll %cl, %eax
 ; X86-SLOW-NEXT:    shrl %edi
-; X86-SLOW-NEXT:    movl %ecx, %ebx
-; X86-SLOW-NEXT:    notb %bl
-; X86-SLOW-NEXT:    movl %ebx, %ecx
-; X86-SLOW-NEXT:    movb %bl, {{[-0-9]+}}(%e{{[sb]}}p) # 1-byte Spill
+; X86-SLOW-NEXT:    movl %edx, %ecx
 ; X86-SLOW-NEXT:    shrl %cl, %edi
-; X86-SLOW-NEXT:    orl %esi, %edi
+; X86-SLOW-NEXT:    orl %eax, %edi
 ; X86-SLOW-NEXT:    movl {{[-0-9]+}}(%e{{[sb]}}p), %esi # 4-byte Reload
 ; X86-SLOW-NEXT:    movl %esi, %eax
 ; X86-SLOW-NEXT:    movl 56(%ebp), %ecx
 ; X86-SLOW-NEXT:    # kill: def $cl killed $cl killed $ecx
 ; X86-SLOW-NEXT:    shll %cl, %eax
-; X86-SLOW-NEXT:    shrl %edx
-; X86-SLOW-NEXT:    movl %ebx, %ecx
-; X86-SLOW-NEXT:    shrl %cl, %edx
-; X86-SLOW-NEXT:    orl %eax, %edx
-; X86-SLOW-NEXT:    movl {{[-0-9]+}}(%e{{[sb]}}p), %ebx # 4-byte Reload
-; X86-SLOW-NEXT:    movl %ebx, %eax
+; X86-SLOW-NEXT:    shrl %ebx
+; X86-SLOW-NEXT:    movl %edx, %ecx
+; X86-SLOW-NEXT:    shrl %cl, %ebx
+; X86-SLOW-NEXT:    orl %eax, %ebx
 ; X86-SLOW-NEXT:    movl 56(%ebp), %ecx
 ; X86-SLOW-NEXT:    # kill: def $cl killed $cl killed $ecx
+; X86-SLOW-NEXT:    movl {{[-0-9]+}}(%e{{[sb]}}p), %eax # 4-byte Reload
 ; X86-SLOW-NEXT:    shll %cl, %eax
 ; X86-SLOW-NEXT:    shrl %esi
-; X86-SLOW-NEXT:    movzbl {{[-0-9]+}}(%e{{[sb]}}p), %ecx # 1-byte Folded Reload
+; X86-SLOW-NEXT:    movl %edx, %ecx
 ; X86-SLOW-NEXT:    shrl %cl, %esi
 ; X86-SLOW-NEXT:    orl %eax, %esi
-; X86-SLOW-NEXT:    movl 56(%ebp), %ecx
-; X86-SLOW-NEXT:    # kill: def $cl killed $cl killed $ecx
-; X86-SLOW-NEXT:    movl {{[-0-9]+}}(%e{{[sb]}}p), %eax # 4-byte Reload
-; X86-SLOW-NEXT:    shll %cl, %eax
-; X86-SLOW-NEXT:    shrl %ebx
-; X86-SLOW-NEXT:    movzbl {{[-0-9]+}}(%e{{[sb]}}p), %ecx # 1-byte Folded Reload
-; X86-SLOW-NEXT:    shrl %cl, %ebx
-; X86-SLOW-NEXT:    orl %eax, %ebx
 ; X86-SLOW-NEXT:    movl 8(%ebp), %eax
-; X86-SLOW-NEXT:    movl %ebx, 12(%eax)
-; X86-SLOW-NEXT:    movl %esi, 8(%eax)
-; X86-SLOW-NEXT:    movl %edx, 4(%eax)
-; X86-SLOW-NEXT:    movl %edi, (%eax)
+; X86-SLOW-NEXT:    movl %esi, 12(%eax)
+; X86-SLOW-NEXT:    movl %ebx, 8(%eax)
+; X86-SLOW-NEXT:    movl %edi, 4(%eax)
+; X86-SLOW-NEXT:    movl {{[-0-9]+}}(%e{{[sb]}}p), %ecx # 4-byte Reload
+; X86-SLOW-NEXT:    movl %ecx, (%eax)
 ; X86-SLOW-NEXT:    leal -12(%ebp), %esp
 ; X86-SLOW-NEXT:    popl %esi
 ; X86-SLOW-NEXT:    popl %edi
diff --git a/llvm/test/CodeGen/X86/fshr.ll b/llvm/test/CodeGen/X86/fshr.ll
@@ -322,79 +322,79 @@ define i128 @var_shift_i128(i128 %x, i128 %y, i128 %z) nounwind {
 ; X86-SLOW-NEXT:    subl $16, %esp
 ; X86-SLOW-NEXT:    movl 24(%ebp), %edx
 ; X86-SLOW-NEXT:    movl 28(%ebp), %esi
-; X86-SLOW-NEXT:    movl 48(%ebp), %ebx
+; X86-SLOW-NEXT:    movl 48(%ebp), %edi
 ; X86-SLOW-NEXT:    movl 56(%ebp), %eax
 ; X86-SLOW-NEXT:    testb $64, %al
-; X86-SLOW-NEXT:    movl 52(%ebp), %edi
+; X86-SLOW-NEXT:    movl 52(%ebp), %eax
 ; X86-SLOW-NEXT:    je .LBB6_1
 ; X86-SLOW-NEXT:  # %bb.2:
-; X86-SLOW-NEXT:    movl %ebx, (%esp) # 4-byte Spill
-; X86-SLOW-NEXT:    movl %edx, %ebx
+; X86-SLOW-NEXT:    movl %edi, (%esp) # 4-byte Spill
+; X86-SLOW-NEXT:    movl %edx, %edi
 ; X86-SLOW-NEXT:    movl 32(%ebp), %edx
-; X86-SLOW-NEXT:    movl %edi, %eax
-; X86-SLOW-NEXT:    movl %esi, %edi
+; X86-SLOW-NEXT:    movl %eax, %ecx
+; X86-SLOW-NEXT:    movl %esi, %eax
 ; X86-SLOW-NEXT:    movl 36(%ebp), %esi
 ; X86-SLOW-NEXT:    jmp .LBB6_3
 ; X86-SLOW-NEXT:  .LBB6_1:
-; X86-SLOW-NEXT:    movl 40(%ebp), %eax
-; X86-SLOW-NEXT:    movl %eax, (%esp) # 4-byte Spill
-; X86-SLOW-NEXT:    movl 44(%ebp), %eax
+; X86-SLOW-NEXT:    movl 40(%ebp), %ecx
+; X86-SLOW-NEXT:    movl %ecx, (%esp) # 4-byte Spill
+; X86-SLOW-NEXT:    movl 44(%ebp), %ecx
 ; X86-SLOW-NEXT:  .LBB6_3:
-; X86-SLOW-NEXT:    movl 56(%ebp), %ecx
-; X86-SLOW-NEXT:    testb $32, %cl
+; X86-SLOW-NEXT:    movl 56(%ebp), %ebx
+; X86-SLOW-NEXT:    testb $32, %bl
 ; X86-SLOW-NEXT:    je .LBB6_4
 ; X86-SLOW-NEXT:  # %bb.5:
-; X86-SLOW-NEXT:    movl %edi, {{[-0-9]+}}(%e{{[sb]}}p) # 4-byte Spill
+; X86-SLOW-NEXT:    movl %eax, {{[-0-9]+}}(%e{{[sb]}}p) # 4-byte Spill
 ; X86-SLOW-NEXT:    movl %edx, {{[-0-9]+}}(%e{{[sb]}}p) # 4-byte Spill
+; X86-SLOW-NEXT:    movl %ecx, %ebx
 ; X86-SLOW-NEXT:    jmp .LBB6_6
 ; X86-SLOW-NEXT:  .LBB6_4:
 ; X86-SLOW-NEXT:    movl %edx, %esi
+; X86-SLOW-NEXT:    movl %eax, {{[-0-9]+}}(%e{{[sb]}}p) # 4-byte Spill
 ; X86-SLOW-NEXT:    movl %edi, {{[-0-9]+}}(%e{{[sb]}}p) # 4-byte Spill
-; X86-SLOW-NEXT:    movl %ebx, {{[-0-9]+}}(%e{{[sb]}}p) # 4-byte Spill
-; X86-SLOW-NEXT:    movl %eax, %ebx
-; X86-SLOW-NEXT:    movl (%esp), %eax # 4-byte Reload
+; X86-SLOW-NEXT:    movl %ecx, %edi
+; X86-SLOW-NEXT:    movl (%esp), %ebx # 4-byte Reload
 ; X86-SLOW-NEXT:  .LBB6_6:
-; X86-SLOW-NEXT:    shrl %cl, %eax
-; X86-SLOW-NEXT:    movl %eax, %edx
-; X86-SLOW-NEXT:    movl %ecx, %eax
-; X86-SLOW-NEXT:    notb %al
-; X86-SLOW-NEXT:    movl %ebx, %edi
-; X86-SLOW-NEXT:    addl %ebx, %ebx
-; X86-SLOW-NEXT:    movl %eax, %ecx
-; X86-SLOW-NEXT:    shll %cl, %ebx
-; X86-SLOW-NEXT:    orl %edx, %ebx
-; X86-SLOW-NEXT:    movl %ebx, (%esp) # 4-byte Spill
 ; X86-SLOW-NEXT:    movl 56(%ebp), %ecx
-; X86-SLOW-NEXT:    # kill: def $cl killed $cl killed $ecx
-; X86-SLOW-NEXT:    shrl %cl, %edi
-; X86-SLOW-NEXT:    movl {{[-0-9]+}}(%e{{[sb]}}p), %ebx # 4-byte Reload
-; X86-SLOW-NEXT:    leal (%ebx,%ebx), %edx
-; X86-SLOW-NEXT:    movl %eax, %ecx
-; X86-SLOW-NEXT:    shll %cl, %edx
-; X86-SLOW-NEXT:    orl %edi, %edx
+; X86-SLOW-NEXT:    shrl %cl, %ebx
+; X86-SLOW-NEXT:    movl %ecx, %edx
+; X86-SLOW-NEXT:    notb %dl
+; X86-SLOW-NEXT:    movl %edi, %eax
+; X86-SLOW-NEXT:    addl %edi, %edi
+; X86-SLOW-NEXT:    movl %edx, %ecx
+; X86-SLOW-NEXT:    shll %cl, %edi
+; X86-SLOW-NEXT:    orl %ebx, %edi
+; X86-SLOW-NEXT:    movl %edi, (%esp) # 4-byte Spill
 ; X86-SLOW-NEXT:    movl 56(%ebp), %ecx
 ; X86-SLOW-NEXT:    # kill: def $cl killed $cl killed $ecx
-; X86-SLOW-NEXT:    shrl %cl, %ebx
-; X86-SLOW-NEXT:    movl %ebx, {{[-0-9]+}}(%e{{[sb]}}p) # 4-byte Spill
+; X86-SLOW-NEXT:    shrl %cl, %eax
 ; X86-SLOW-NEXT:    movl {{[-0-9]+}}(%e{{[sb]}}p), %edi # 4-byte Reload
 ; X86-SLOW-NEXT:    leal (%edi,%edi), %ebx
-; X86-SLOW-NEXT:    movl %eax, %ecx
+; X86-SLOW-NEXT:    movl %edx, %ecx
 ; X86-SLOW-NEXT:    shll %cl, %ebx
-; X86-SLOW-NEXT:    orl {{[-0-9]+}}(%e{{[sb]}}p), %ebx # 4-byte Folded Reload
+; X86-SLOW-NEXT:    orl %eax, %ebx
 ; X86-SLOW-NEXT:    movl 56(%ebp), %ecx
 ; X86-SLOW-NEXT:    # kill: def $cl killed $cl killed $ecx
 ; X86-SLOW-NEXT:    shrl %cl, %edi
+; X86-SLOW-NEXT:    movl %edi, {{[-0-9]+}}(%e{{[sb]}}p) # 4-byte Spill
+; X86-SLOW-NEXT:    movl {{[-0-9]+}}(%e{{[sb]}}p), %eax # 4-byte Reload
+; X86-SLOW-NEXT:    leal (%eax,%eax), %edi
+; X86-SLOW-NEXT:    movl %edx, %ecx
+; X86-SLOW-NEXT:    shll %cl, %edi
+; X86-SLOW-NEXT:    orl {{[-0-9]+}}(%e{{[sb]}}p), %edi # 4-byte Folded Reload
+; X86-SLOW-NEXT:    movl 56(%ebp), %ecx
+; X86-SLOW-NEXT:    # kill: def $cl killed $cl killed $ecx
+; X86-SLOW-NEXT:    shrl %cl, %eax
 ; X86-SLOW-NEXT:    addl %esi, %esi
-; X86-SLOW-NEXT:    movl %eax, %ecx
+; X86-SLOW-NEXT:    movl %edx, %ecx
 ; X86-SLOW-NEXT:    shll %cl, %esi
-; X86-SLOW-NEXT:    orl %edi, %esi
-; X86-SLOW-NEXT:    movl 8(%ebp), %ecx
-; X86-SLOW-NEXT:    movl %esi, 12(%ecx)
-; X86-SLOW-NEXT:    movl %ebx, 8(%ecx)
-; X86-SLOW-NEXT:    movl %edx, 4(%ecx)
-; X86-SLOW-NEXT:    movl (%esp), %eax # 4-byte Reload
-; X86-SLOW-NEXT:    movl %eax, (%ecx)
-; X86-SLOW-NEXT:    movl %ecx, %eax
+; X86-SLOW-NEXT:    orl %eax, %esi
+; X86-SLOW-NEXT:    movl 8(%ebp), %eax
+; X86-SLOW-NEXT:    movl %esi, 12(%eax)
+; X86-SLOW-NEXT:    movl %edi, 8(%eax)
+; X86-SLOW-NEXT:    movl %ebx, 4(%eax)
+; X86-SLOW-NEXT:    movl (%esp), %ecx # 4-byte Reload
+; X86-SLOW-NEXT:    movl %ecx, (%eax)
 ; X86-SLOW-NEXT:    leal -12(%ebp), %esp
 ; X86-SLOW-NEXT:    popl %esi
 ; X86-SLOW-NEXT:    popl %edi
