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d0dbe02fd2
The C and C++ semantics for compare_exchange require it to return a bool
indicating success. This gets mapped to LLVM IR which follows each cmpxchg with
an icmp of the value loaded against the desired value.
When lowered to ldxr/stxr loops, this extra comparison is redundant: its
results are implicit in the control-flow of the function.
This commit makes two changes: it replaces that icmp with appropriate PHI
nodes, and then makes sure earlyCSE is called after expansion to actually make
use of the opportunities revealed.
I've also added -{arm,aarch64}-enable-atomic-tidy options, so that
existing fragile tests aren't perturbed too much by the change. Many
of them either rely on undef/unreachable too pervasively to be
restored to something well-defined (particularly while making sure
they test the same obscure assert from many years ago), or depend on a
particular CFG shape, which is disrupted by SimplifyCFG.
rdar://problem/16227836
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209883 91177308-0d34-0410-b5e6-96231b3b80d8
137 lines
4.1 KiB
LLVM
137 lines
4.1 KiB
LLVM
; RUN: llc -mtriple=arm-eabi -arm-atomic-cfg-tidy=0 %s -o - | FileCheck -check-prefix=ARM %s
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; RUN: llc -mtriple=thumb-eabi -arm-atomic-cfg-tidy=0 %s -o - | FileCheck -check-prefix=THUMB %s
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; RUN: llc -mtriple=thumb-eabi -arm-atomic-cfg-tidy=0 -mcpu=arm1156t2-s -mattr=+thumb2 %s -o - \
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; RUN: | FileCheck -check-prefix=T2 %s
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; RUN: llc -mtriple=thumbv8-eabi -arm-atomic-cfg-tidy=0 %s -o - | FileCheck -check-prefix=V8 %s
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; FIXME: The -march=thumb test doesn't change if -disable-peephole is specified.
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%struct.Foo = type { i8* }
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; ARM: foo
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; THUMB: foo
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; T2: foo
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define %struct.Foo* @foo(%struct.Foo* %this, i32 %acc) nounwind readonly align 2 {
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entry:
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%scevgep = getelementptr %struct.Foo* %this, i32 1
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br label %tailrecurse
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tailrecurse: ; preds = %sw.bb, %entry
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%lsr.iv2 = phi %struct.Foo* [ %scevgep3, %sw.bb ], [ %scevgep, %entry ]
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%lsr.iv = phi i32 [ %lsr.iv.next, %sw.bb ], [ 1, %entry ]
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%acc.tr = phi i32 [ %or, %sw.bb ], [ %acc, %entry ]
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%lsr.iv24 = bitcast %struct.Foo* %lsr.iv2 to i8**
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%scevgep5 = getelementptr i8** %lsr.iv24, i32 -1
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%tmp2 = load i8** %scevgep5
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%0 = ptrtoint i8* %tmp2 to i32
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; ARM: ands {{r[0-9]+}}, {{r[0-9]+}}, #3
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; ARM-NEXT: beq
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; THUMB: movs r[[R0:[0-9]+]], #3
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; THUMB-NEXT: ands r[[R0]], r
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; THUMB-NEXT: cmp r[[R0]], #0
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; THUMB-NEXT: beq
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; T2: ands {{r[0-9]+}}, {{r[0-9]+}}, #3
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; T2-NEXT: beq
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%and = and i32 %0, 3
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%tst = icmp eq i32 %and, 0
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br i1 %tst, label %sw.bb, label %tailrecurse.switch
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tailrecurse.switch: ; preds = %tailrecurse
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; V8-LABEL: %tailrecurse.switch
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; V8: cmp
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; V8-NEXT: beq
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; V8-NEXT: %tailrecurse.switch
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; V8: cmp
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; V8-NEXT: beq
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; V8-NEXT: %tailrecurse.switch
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; V8: cmp
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; V8-NEXT: beq
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; V8-NEXT: b
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; The trailing space in the last line checks that the branch is unconditional
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switch i32 %and, label %sw.epilog [
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i32 1, label %sw.bb
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i32 3, label %sw.bb6
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i32 2, label %sw.bb8
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]
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sw.bb: ; preds = %tailrecurse.switch, %tailrecurse
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%shl = shl i32 %acc.tr, 1
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%or = or i32 %and, %shl
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%lsr.iv.next = add i32 %lsr.iv, 1
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%scevgep3 = getelementptr %struct.Foo* %lsr.iv2, i32 1
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br label %tailrecurse
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sw.bb6: ; preds = %tailrecurse.switch
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ret %struct.Foo* %lsr.iv2
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sw.bb8: ; preds = %tailrecurse.switch
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%tmp1 = add i32 %acc.tr, %lsr.iv
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%add.ptr11 = getelementptr inbounds %struct.Foo* %this, i32 %tmp1
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ret %struct.Foo* %add.ptr11
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sw.epilog: ; preds = %tailrecurse.switch
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ret %struct.Foo* undef
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}
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; Another test that exercises the AND/TST peephole optimization and also
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; generates a predicated ANDS instruction. Check that the predicate is printed
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; after the "S" modifier on the instruction.
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%struct.S = type { i8* (i8*)*, [1 x i8] }
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; ARM: bar
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; THUMB: bar
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; T2: bar
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; V8-LABEL: bar:
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define internal zeroext i8 @bar(%struct.S* %x, %struct.S* nocapture %y) nounwind readonly {
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entry:
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%0 = getelementptr inbounds %struct.S* %x, i32 0, i32 1, i32 0
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%1 = load i8* %0, align 1
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%2 = zext i8 %1 to i32
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; ARM: ands
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; THUMB: ands
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; T2: ands
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; V8: ands
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; V8-NEXT: beq
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%3 = and i32 %2, 112
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%4 = icmp eq i32 %3, 0
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br i1 %4, label %return, label %bb
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bb: ; preds = %entry
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; V8-NEXT: %bb
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%5 = getelementptr inbounds %struct.S* %y, i32 0, i32 1, i32 0
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%6 = load i8* %5, align 1
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%7 = zext i8 %6 to i32
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; ARM: andsne
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; THUMB: ands
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; T2: andsne
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; V8: ands
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; V8-NEXT: beq
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%8 = and i32 %7, 112
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%9 = icmp eq i32 %8, 0
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br i1 %9, label %return, label %bb2
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bb2: ; preds = %bb
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; V8-NEXT: %bb2
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; V8-NEXT: cmp
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; V8-NEXT: it ne
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; V8-NEXT: cmpne
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; V8-NEXT: bne
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%10 = icmp eq i32 %3, 16
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%11 = icmp eq i32 %8, 16
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%or.cond = or i1 %10, %11
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br i1 %or.cond, label %bb4, label %return
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bb4: ; preds = %bb2
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%12 = ptrtoint %struct.S* %x to i32
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%phitmp = trunc i32 %12 to i8
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ret i8 %phitmp
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return: ; preds = %bb2, %bb, %entry
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ret i8 1
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}
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