652bcf685c
Depending on the TLSMode many thread-local accesses on x86 can be expressed by adding a %fs: segment register to an addressing mode. Even if there are mutliple users of a `llvm.threadlocal.address` intrinsic it is generally not worth sharing the value in a register but instead fold the %fs access into multiple addressing modes. Hence this changes CodeGenPrepare to duplicate the `llvm.threadlocal.address` intrinsic as necessary. Introduces a new `TargetLowering::addressingModeSupportsTLS` callback that allows targets to indicate whether TLS accesses can be part of an addressing mode. This is fixing a performance problem, as this folding of TLS-accesses into multiple addressing modes happened naturally before the introduction of the `llvm.threadlocal.address` intrinsic, but regressed due to `SelectionDAG` keeping things in registers when accessed across basic blocks, so CodeGenPrepare needs to duplicate to mitigate this. We see a ~0.5% recovery in a codebase with heavy TLS usage (HHVM). This fixes most of #87437
194 lines
6.0 KiB
LLVM
194 lines
6.0 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 4
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; RUN: llc -o - %s | FileCheck %s --check-prefix=NOPIC
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; RUN: llc -o - %s -relocation-model=pic | FileCheck %s --check-prefix=PIC
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; RUN: llc -o - %s -relocation-model=pic -enable-tlsdesc | FileCheck %s --check-prefix=TLSDESC
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target triple = "x86_64--linux-gnu"
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declare void @effect()
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declare nonnull ptr @llvm.threadlocal.address.p0(ptr nonnull)
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@foo_local = dso_local thread_local(localexec) global i32 0, align 4
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define i32 @func_local_tls(i32 %arg0, i64 %arg1) nounwind {
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; NOPIC-LABEL: func_local_tls:
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; NOPIC: # %bb.0: # %entry
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; NOPIC-NEXT: pushq %rbp
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; NOPIC-NEXT: pushq %rbx
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; NOPIC-NEXT: pushq %rax
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; NOPIC-NEXT: movl %fs:foo_local@TPOFF, %ebp
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; NOPIC-NEXT: testl %edi, %edi
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; NOPIC-NEXT: movl %ebp, %eax
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; NOPIC-NEXT: jne .LBB0_2
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; NOPIC-NEXT: # %bb.1: # %if.then
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; NOPIC-NEXT: movq %rsi, %rbx
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; NOPIC-NEXT: callq effect@PLT
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; NOPIC-NEXT: movl %fs:foo_local@TPOFF+168(,%rbx,4), %eax
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; NOPIC-NEXT: .LBB0_2: # %if.end
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; NOPIC-NEXT: addl %ebp, %eax
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; NOPIC-NEXT: addq $8, %rsp
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; NOPIC-NEXT: popq %rbx
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; NOPIC-NEXT: popq %rbp
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; NOPIC-NEXT: retq
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;
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; PIC-LABEL: func_local_tls:
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; PIC: # %bb.0: # %entry
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; PIC-NEXT: pushq %rbp
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; PIC-NEXT: pushq %r14
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; PIC-NEXT: pushq %rbx
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; PIC-NEXT: movl %fs:.Lfoo_local$local@TPOFF, %ebp
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; PIC-NEXT: testl %edi, %edi
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; PIC-NEXT: movl %ebp, %eax
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; PIC-NEXT: jne .LBB0_2
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; PIC-NEXT: # %bb.1: # %if.then
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; PIC-NEXT: movq %rsi, %rbx
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; PIC-NEXT: movq %fs:0, %rax
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; PIC-NEXT: leaq .Lfoo_local$local@TPOFF(%rax), %r14
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; PIC-NEXT: callq effect@PLT
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; PIC-NEXT: movl 168(%r14,%rbx,4), %eax
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; PIC-NEXT: .LBB0_2: # %if.end
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; PIC-NEXT: addl %ebp, %eax
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; PIC-NEXT: popq %rbx
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; PIC-NEXT: popq %r14
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; PIC-NEXT: popq %rbp
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; PIC-NEXT: retq
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;
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; TLSDESC-LABEL: func_local_tls:
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; TLSDESC: # %bb.0: # %entry
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; TLSDESC-NEXT: pushq %rbp
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; TLSDESC-NEXT: pushq %r14
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; TLSDESC-NEXT: pushq %rbx
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; TLSDESC-NEXT: movl %fs:.Lfoo_local$local@TPOFF, %ebp
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; TLSDESC-NEXT: testl %edi, %edi
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; TLSDESC-NEXT: movl %ebp, %eax
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; TLSDESC-NEXT: jne .LBB0_2
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; TLSDESC-NEXT: # %bb.1: # %if.then
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; TLSDESC-NEXT: movq %rsi, %rbx
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; TLSDESC-NEXT: movq %fs:0, %rax
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; TLSDESC-NEXT: leaq .Lfoo_local$local@TPOFF(%rax), %r14
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; TLSDESC-NEXT: callq effect@PLT
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; TLSDESC-NEXT: movl 168(%r14,%rbx,4), %eax
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; TLSDESC-NEXT: .LBB0_2: # %if.end
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; TLSDESC-NEXT: addl %ebp, %eax
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; TLSDESC-NEXT: popq %rbx
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; TLSDESC-NEXT: popq %r14
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; TLSDESC-NEXT: popq %rbp
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; TLSDESC-NEXT: retq
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entry:
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%addr = tail call ptr @llvm.threadlocal.address.p0(ptr @foo_local)
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%load0 = load i32, ptr %addr, align 4
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%cond = icmp eq i32 %arg0, 0
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br i1 %cond, label %if.then, label %if.end
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if.then:
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tail call void @effect()
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%x = add i64 %arg1, 42
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%addr1 = getelementptr inbounds i32, ptr %addr, i64 %x
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%load1 = load i32, ptr %addr1, align 4
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br label %if.end
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if.end:
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%phi = phi i32 [ %load1, %if.then ], [ %load0, %entry ]
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%ret = add i32 %phi, %load0
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ret i32 %ret
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}
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@foo_nonlocal = thread_local global i32 0, align 4
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define i32 @func_nonlocal_tls(i32 %arg0, i64 %arg1) nounwind {
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; NOPIC-LABEL: func_nonlocal_tls:
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; NOPIC: # %bb.0: # %entry
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; NOPIC-NEXT: pushq %rbp
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; NOPIC-NEXT: pushq %r14
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; NOPIC-NEXT: pushq %rbx
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; NOPIC-NEXT: movq foo_nonlocal@GOTTPOFF(%rip), %r14
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; NOPIC-NEXT: movl %fs:(%r14), %ebp
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; NOPIC-NEXT: testl %edi, %edi
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; NOPIC-NEXT: movl %ebp, %eax
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; NOPIC-NEXT: jne .LBB1_2
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; NOPIC-NEXT: # %bb.1: # %if.then
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; NOPIC-NEXT: movq %rsi, %rbx
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; NOPIC-NEXT: callq effect@PLT
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; NOPIC-NEXT: movl %fs:168(%r14,%rbx,4), %eax
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; NOPIC-NEXT: .LBB1_2: # %if.end
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; NOPIC-NEXT: addl %ebp, %eax
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; NOPIC-NEXT: popq %rbx
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; NOPIC-NEXT: popq %r14
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; NOPIC-NEXT: popq %rbp
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; NOPIC-NEXT: retq
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;
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; PIC-LABEL: func_nonlocal_tls:
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; PIC: # %bb.0: # %entry
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; PIC-NEXT: pushq %rbp
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; PIC-NEXT: pushq %r15
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; PIC-NEXT: pushq %r14
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; PIC-NEXT: pushq %rbx
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; PIC-NEXT: pushq %rax
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; PIC-NEXT: movq %rsi, %rbx
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; PIC-NEXT: movl %edi, %ebp
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; PIC-NEXT: data16
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; PIC-NEXT: leaq foo_nonlocal@TLSGD(%rip), %rdi
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; PIC-NEXT: data16
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; PIC-NEXT: data16
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; PIC-NEXT: rex64
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; PIC-NEXT: callq __tls_get_addr@PLT
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; PIC-NEXT: movq %rax, %r14
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; PIC-NEXT: movl (%rax), %r15d
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; PIC-NEXT: testl %ebp, %ebp
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; PIC-NEXT: movl %r15d, %eax
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; PIC-NEXT: jne .LBB1_2
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; PIC-NEXT: # %bb.1: # %if.then
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; PIC-NEXT: callq effect@PLT
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; PIC-NEXT: movl 168(%r14,%rbx,4), %eax
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; PIC-NEXT: .LBB1_2: # %if.end
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; PIC-NEXT: addl %r15d, %eax
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; PIC-NEXT: addq $8, %rsp
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; PIC-NEXT: popq %rbx
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; PIC-NEXT: popq %r14
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; PIC-NEXT: popq %r15
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; PIC-NEXT: popq %rbp
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; PIC-NEXT: retq
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;
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; TLSDESC-LABEL: func_nonlocal_tls:
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; TLSDESC: # %bb.0: # %entry
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; TLSDESC-NEXT: pushq %rbp
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; TLSDESC-NEXT: pushq %r14
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; TLSDESC-NEXT: pushq %rbx
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; TLSDESC-NEXT: leaq foo_nonlocal@tlsdesc(%rip), %rax
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; TLSDESC-NEXT: callq *foo_nonlocal@tlscall(%rax)
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; TLSDESC-NEXT: movl %fs:(%rax), %ebp
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; TLSDESC-NEXT: testl %edi, %edi
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; TLSDESC-NEXT: movl %ebp, %ecx
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; TLSDESC-NEXT: jne .LBB1_2
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; TLSDESC-NEXT: # %bb.1: # %if.then
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; TLSDESC-NEXT: movq %rsi, %rbx
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; TLSDESC-NEXT: addq %fs:0, %rax
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; TLSDESC-NEXT: movq %rax, %r14
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; TLSDESC-NEXT: callq effect@PLT
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; TLSDESC-NEXT: movl 168(%r14,%rbx,4), %ecx
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; TLSDESC-NEXT: .LBB1_2: # %if.end
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; TLSDESC-NEXT: addl %ebp, %ecx
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; TLSDESC-NEXT: movl %ecx, %eax
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; TLSDESC-NEXT: popq %rbx
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; TLSDESC-NEXT: popq %r14
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; TLSDESC-NEXT: popq %rbp
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; TLSDESC-NEXT: retq
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entry:
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%addr = tail call ptr @llvm.threadlocal.address.p0(ptr @foo_nonlocal)
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%load0 = load i32, ptr %addr, align 4
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%cond = icmp eq i32 %arg0, 0
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br i1 %cond, label %if.then, label %if.end
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if.then:
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tail call void @effect()
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%x = add i64 %arg1, 42
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%addr1 = getelementptr inbounds i32, ptr %addr, i64 %x
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%load1 = load i32, ptr %addr1, align 4
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br label %if.end
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if.end:
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%phi = phi i32 [ %load1, %if.then ], [ %load0, %entry ]
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%ret = add i32 %phi, %load0
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ret i32 %ret
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}
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