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https://github.com/RPCS3/llvm-mirror.git
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ef448d0349
This patch contains a pass that transforms CBZ/CBNZ/TBZ/TBNZ instructions into a conditional branch (Bcc), when the NZCV flags can be set for "free". This is preferred on targets that have more flexibility when scheduling Bcc instructions as compared to CBZ/CBNZ/TBZ/TBNZ (assuming all other variables are equal). This can reduce register pressure and is also the default behavior for GCC. A few examples: add w8, w0, w1 -> cmn w0, w1 ; CMN is an alias of ADDS. cbz w8, .LBB_2 -> b.eq .LBB0_2 ; single def/use of w8 removed. add w8, w0, w1 -> adds w8, w0, w1 ; w8 has multiple uses. cbz w8, .LBB1_2 -> b.eq .LBB1_2 sub w8, w0, w1 -> subs w8, w0, w1 ; w8 has multiple uses. tbz w8, #31, .LBB6_2 -> b.ge .LBB6_2 In looking at all current sub-target machine descriptions, this transformation appears to be either positive or neutral. Differential Revision: https://reviews.llvm.org/D34220. llvm-svn: 306144
362 lines
5.9 KiB
LLVM
362 lines
5.9 KiB
LLVM
; RUN: llc < %s -O1 -mtriple=aarch64-eabi -aarch64-enable-cond-br-tune=false | FileCheck %s
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declare void @t()
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define void @test1(i32 %a) {
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; CHECK-LABEL: @test1
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entry:
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%sub = add nsw i32 %a, -12
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%cmp = icmp slt i32 %sub, 0
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br i1 %cmp, label %if.then, label %if.end
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; CHECK: sub [[CMP:w[0-9]+]], w0, #12
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; CHECK: tbnz [[CMP]], #31
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if.then:
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call void @t()
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br label %if.end
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if.end:
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ret void
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}
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define void @test2(i64 %a) {
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; CHECK-LABEL: @test2
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entry:
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%sub = add nsw i64 %a, -12
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%cmp = icmp slt i64 %sub, 0
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br i1 %cmp, label %if.then, label %if.end
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; CHECK: sub [[CMP:x[0-9]+]], x0, #12
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; CHECK: tbnz [[CMP]], #63
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if.then:
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call void @t()
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br label %if.end
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if.end:
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ret void
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}
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define void @test3(i32 %a) {
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; CHECK-LABEL: @test3
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entry:
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%sub = add nsw i32 %a, -12
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%cmp = icmp sgt i32 %sub, -1
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br i1 %cmp, label %if.then, label %if.end
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; CHECK: sub [[CMP:w[0-9]+]], w0, #12
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; CHECK: tbnz [[CMP]], #31
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if.then:
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call void @t()
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br label %if.end
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if.end:
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ret void
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}
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define void @test4(i64 %a) {
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; CHECK-LABEL: @test4
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entry:
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%sub = add nsw i64 %a, -12
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%cmp = icmp sgt i64 %sub, -1
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br i1 %cmp, label %if.then, label %if.end
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; CHECK: sub [[CMP:x[0-9]+]], x0, #12
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; CHECK: tbnz [[CMP]], #63
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if.then:
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call void @t()
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br label %if.end
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if.end:
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ret void
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}
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define void @test5(i32 %a) {
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; CHECK-LABEL: @test5
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entry:
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%sub = add nsw i32 %a, -12
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%cmp = icmp sge i32 %sub, 0
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br i1 %cmp, label %if.then, label %if.end
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; CHECK: sub [[CMP:w[0-9]+]], w0, #12
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; CHECK: tbnz [[CMP]], #31
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if.then:
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call void @t()
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br label %if.end
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if.end:
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ret void
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}
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define void @test6(i64 %a) {
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; CHECK-LABEL: @test6
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entry:
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%sub = add nsw i64 %a, -12
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%cmp = icmp sge i64 %sub, 0
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br i1 %cmp, label %if.then, label %if.end
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; CHECK: sub [[CMP:x[0-9]+]], x0, #12
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; CHECK: tbnz [[CMP]], #63
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if.then:
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call void @t()
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br label %if.end
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if.end:
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ret void
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}
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define void @test7(i32 %a) {
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; CHECK-LABEL: @test7
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entry:
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%sub = sub nsw i32 %a, 12
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%cmp = icmp slt i32 %sub, 0
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br i1 %cmp, label %if.then, label %if.end
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; CHECK: sub [[CMP:w[0-9]+]], w0, #12
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; CHECK: tbnz [[CMP]], #31
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if.then:
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call void @t()
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br label %if.end
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if.end:
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ret void
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}
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define void @test8(i64 %val1, i64 %val2, i64 %val3) {
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; CHECK-LABEL: @test8
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%and1 = and i64 %val1, %val2
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%tst1 = icmp slt i64 %and1, 0
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br i1 %tst1, label %if.then1, label %if.end
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; CHECK: tst x0, x1
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; CHECK-NEXT: b.ge
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if.then1:
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%and2 = and i64 %val2, %val3
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%tst2 = icmp sge i64 %and2, 0
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br i1 %tst2, label %if.then2, label %if.end
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; CHECK: and [[CMP:x[0-9]+]], x1, x2
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; CHECK-NOT: cmp
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; CHECK: tbnz [[CMP]], #63
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if.then2:
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%shifted_op1 = shl i64 %val2, 63
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%shifted_and1 = and i64 %val1, %shifted_op1
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%tst3 = icmp slt i64 %shifted_and1, 0
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br i1 %tst3, label %if.then3, label %if.end
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; CHECK: tst x0, x1, lsl #63
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; CHECK: b.ge
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if.then3:
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%shifted_op2 = shl i64 %val2, 62
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%shifted_and2 = and i64 %val1, %shifted_op2
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%tst4 = icmp sge i64 %shifted_and2, 0
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br i1 %tst4, label %if.then4, label %if.end
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; CHECK: tst x0, x1, lsl #62
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; CHECK: b.lt
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if.then4:
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call void @t()
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br label %if.end
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if.end:
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ret void
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}
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define void @test9(i64 %val1) {
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; CHECK-LABEL: @test9
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%tst = icmp slt i64 %val1, 0
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br i1 %tst, label %if.then, label %if.end
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; CHECK-NOT: cmp
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; CHECK: tbnz x0, #63
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if.then:
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call void @t()
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br label %if.end
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if.end:
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ret void
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}
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define void @test10(i64 %val1) {
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; CHECK-LABEL: @test10
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%tst = icmp slt i64 %val1, 0
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br i1 %tst, label %if.then, label %if.end
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; CHECK-NOT: cmp
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; CHECK: tbnz x0, #63
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if.then:
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call void @t()
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br label %if.end
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if.end:
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ret void
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}
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define void @test11(i64 %val1, i64* %ptr) {
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; CHECK-LABEL: @test11
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; CHECK: ldr [[CMP:x[0-9]+]], [x1]
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; CHECK-NOT: cmp
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; CHECK: tbnz [[CMP]], #63
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%val = load i64, i64* %ptr
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%tst = icmp slt i64 %val, 0
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br i1 %tst, label %if.then, label %if.end
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if.then:
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call void @t()
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br label %if.end
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if.end:
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ret void
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}
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define void @test12(i64 %val1) {
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; CHECK-LABEL: @test12
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%tst = icmp slt i64 %val1, 0
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br i1 %tst, label %if.then, label %if.end
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; CHECK-NOT: cmp
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; CHECK: tbnz x0, #63
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if.then:
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call void @t()
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br label %if.end
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if.end:
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ret void
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}
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define void @test13(i64 %val1, i64 %val2) {
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; CHECK-LABEL: @test13
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%or = or i64 %val1, %val2
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%tst = icmp slt i64 %or, 0
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br i1 %tst, label %if.then, label %if.end
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; CHECK: orr [[CMP:x[0-9]+]], x0, x1
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; CHECK-NOT: cmp
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; CHECK: tbnz [[CMP]], #63
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if.then:
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call void @t()
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br label %if.end
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if.end:
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ret void
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}
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define void @test14(i1 %cond) {
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; CHECK-LABEL: @test14
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br i1 %cond, label %if.end, label %if.then
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; CHECK-NOT: and
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; CHECK: tbnz w0, #0
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if.then:
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call void @t()
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br label %if.end
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if.end:
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ret void
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}
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define void @test15(i1 %cond) {
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; CHECK-LABEL: @test15
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%cond1 = xor i1 %cond, -1
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br i1 %cond1, label %if.then, label %if.end
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; CHECK-NOT: movn
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; CHECK: tbnz w0, #0
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if.then:
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call void @t()
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br label %if.end
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if.end:
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ret void
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}
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define void @test16(i64 %in) {
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; CHECK-LABEL: @test16
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%shl = shl i64 %in, 3
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%and = and i64 %shl, 32
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%cond = icmp eq i64 %and, 0
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br i1 %cond, label %then, label %end
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; CHECK-NOT: lsl
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; CHECK: tbnz w0, #2
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then:
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call void @t()
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br label %end
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end:
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ret void
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}
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define void @test17(i64 %in) {
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; CHECK-LABEL: @test17
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%shr = ashr i64 %in, 3
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%and = and i64 %shr, 1
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%cond = icmp eq i64 %and, 0
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br i1 %cond, label %then, label %end
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; CHECK-NOT: lsr
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; CHECK: tbnz w0, #3
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then:
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call void @t()
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br label %end
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end:
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ret void
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}
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define void @test18(i32 %in) {
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; CHECK-LABEL: @test18
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%shr = ashr i32 %in, 2
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%cond = icmp sge i32 %shr, 0
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br i1 %cond, label %then, label %end
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; CHECK-NOT: asr
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; CHECK: tbnz w0, #31
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then:
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call void @t()
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br label %end
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end:
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ret void
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}
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define void @test19(i64 %in) {
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; CHECK-LABEL: @test19
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%shl = lshr i64 %in, 3
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%trunc = trunc i64 %shl to i32
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%and = and i32 %trunc, 1
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%cond = icmp eq i32 %and, 0
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br i1 %cond, label %then, label %end
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; CHECK-NOT: ubfx
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; CHECK: tbnz w0, #3
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then:
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call void @t()
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br label %end
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end:
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ret void
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}
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