d2210af332
Current findBestLoopTop can find and move one kind of block to top, a latch block has one successor. Another common case is:
* a latch block
* it has two successors, one is loop header, another is exit
* it has more than one predecessors
If it is below one of its predecessors P, only P can fall through to it, all other predecessors need a jump to it, and another conditional jump to loop header. If it is moved before loop header, all its predecessors jump to it, then fall through to loop header. So all its predecessors except P can reduce one taken branch.
Differential Revision: https://reviews.llvm.org/D43256
llvm-svn: 363471
86 lines
3.4 KiB
LLVM
86 lines
3.4 KiB
LLVM
; RUN: llc < %s -mtriple=arm-linux-gnueabi -asm-verbose=false -verify-machineinstrs | FileCheck %s -check-prefix=CHECK-ARM
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; RUN: llc < %s -mtriple=thumb-linux-gnueabi -asm-verbose=false -verify-machineinstrs | FileCheck %s -check-prefix=CHECK-THUMB
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; RUN: llc < %s -mtriple=armv6-linux-gnueabi -asm-verbose=false -verify-machineinstrs | FileCheck %s -check-prefix=CHECK-ARMV6
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; RUN: llc < %s -mtriple=thumbv6-linux-gnueabi -asm-verbose=false -verify-machineinstrs | FileCheck %s -check-prefix=CHECK-THUMBV6
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; RUN: llc < %s -mtriple=armv7-linux-gnueabi -asm-verbose=false -verify-machineinstrs | FileCheck %s -check-prefix=CHECK-ARMV7
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; RUN: llc < %s -mtriple=thumbv7-linux-gnueabi -asm-verbose=false -verify-machineinstrs | FileCheck %s -check-prefix=CHECK-THUMBV7
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define zeroext i1 @test_cmpxchg_res_i8(i8* %addr, i8 %desired, i8 zeroext %new) {
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entry:
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%0 = cmpxchg i8* %addr, i8 %desired, i8 %new monotonic monotonic
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%1 = extractvalue { i8, i1 } %0, 1
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ret i1 %1
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}
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; CHECK-ARM-LABEL: test_cmpxchg_res_i8
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; CHECK-ARM: bl __sync_val_compare_and_swap_1
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; CHECK-ARM: sub r0, r0, {{r[0-9]+}}
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; CHECK-ARM: rsbs [[REG:r[0-9]+]], r0, #0
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; CHECK-ARM: adc r0, r0, [[REG]]
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; CHECK-THUMB-LABEL: test_cmpxchg_res_i8
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; CHECK-THUMB: bl __sync_val_compare_and_swap_1
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; CHECK-THUMB-NOT: mov [[R1:r[0-7]]], r0
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; CHECK-THUMB: subs [[R1:r[0-7]]], r0, {{r[0-9]+}}
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; CHECK-THUMB: rsbs r0, [[R1]], #0
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; CHECK-THUMB: adcs r0, [[R1]]
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; CHECK-ARMV6-LABEL: test_cmpxchg_res_i8:
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; CHECK-ARMV6-NEXT: .fnstart
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; CHECK-ARMV6-NEXT: uxtb [[DESIRED:r[0-9]+]], r1
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; CHECK-ARMV6-NEXT: [[TRY:.LBB[0-9_]+]]:
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; CHECK-ARMV6-NEXT: ldrexb [[LD:r[0-9]+]], [r0]
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; CHECK-ARMV6-NEXT: cmp [[LD]], [[DESIRED]]
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; CHECK-ARMV6-NEXT: movne [[RES:r[0-9]+]], #0
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; CHECK-ARMV6-NEXT: bxne lr
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; CHECK-ARMV6-NEXT: strexb [[SUCCESS:r[0-9]+]], r2, [r0]
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; CHECK-ARMV6-NEXT: cmp [[SUCCESS]], #0
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; CHECK-ARMV6-NEXT: moveq [[RES]], #1
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; CHECK-ARMV6-NEXT: bxeq lr
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; CHECK-ARMV6-NEXT: b [[TRY]]
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; CHECK-THUMBV6-LABEL: test_cmpxchg_res_i8:
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; CHECK-THUMBV6: mov [[EXPECTED:r[0-9]+]], r1
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; CHECK-THUMBV6-NEXT: bl __sync_val_compare_and_swap_1
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; CHECK-THUMBV6-NEXT: uxtb r1, r4
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; CHECK-THUMBV6-NEXT: subs [[R1:r[0-7]]], r0, {{r[0-9]+}}
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; CHECK-THUMBV6-NEXT: rsbs r0, [[R1]], #0
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; CHECK-THUMBV6-NEXT: adcs r0, [[R1]]
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; CHECK-ARMV7-LABEL: test_cmpxchg_res_i8:
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; CHECK-ARMV7-NEXT: .fnstart
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; CHECK-ARMV7-NEXT: uxtb [[DESIRED:r[0-9]+]], r1
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; CHECK-ARMV7-NEXT: [[TRY:.LBB[0-9_]+]]:
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; CHECK-ARMV7-NEXT: ldrexb [[SUCCESS:r[0-9]+]], [r0]
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; CHECK-ARMV7-NEXT: cmp [[SUCCESS]], r1
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; CHECK-ARMV7-NEXT: bne [[EXIT:.LBB[0-9_]+]]
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; CHECK-ARMV7-NEXT: strexb [[SUCCESS]], r2, [r0]
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; CHECK-ARMV7-NEXT: cmp [[SUCCESS]], #0
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; CHECK-ARMV7-NEXT: moveq r0, #1
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; CHECK-ARMV7-NEXT: bxeq lr
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; CHECK-ARMV7-NEXT: b [[TRY]]
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; CHECK-ARMV7-NEXT: [[EXIT]]:
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; CHECK-ARMV7-NEXT: mov r0, #0
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; CHECK-ARMV7-NEXT: clrex
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; CHECK-ARMV7-NEXT: bx lr
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; CHECK-THUMBV7-LABEL: test_cmpxchg_res_i8:
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; CHECK-THUMBV7-NEXT: .fnstart
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; CHECK-THUMBV7-NEXT: uxtb [[DESIRED:r[0-9]+]], r1
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; CHECK-THUMBV7-NEXT: [[TRYLD:.LBB[0-9_]+]]
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; CHECK-THUMBV7-NEXT: ldrexb [[LD:r[0-9]+]], [r0]
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; CHECK-THUMBV7-NEXT: cmp [[LD]], [[DESIRED]]
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; CHECK-THUMBV7-NEXT: bne [[EXIT:.LBB[0-9_]+]]
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; CHECK-THUMBV7-NEXT: strexb [[SUCCESS:r[0-9]+]], r2, [r0]
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; CHECK-THUMBV7-NEXT: cmp [[SUCCESS]], #0
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; CHECK-THUMBV7-NEXT: itt eq
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; CHECK-THUMBV7-NEXT: moveq r0, #1
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; CHECK-THUMBV7-NEXT: bxeq lr
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; CHECK-THUMBV7-NEXT: b [[TRYLD]]
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; CHECK-THUMBV7-NEXT: [[EXIT]]:
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; CHECK-THUMBV7-NEXT: movs r0, #0
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; CHECK-THUMBV7-NEXT: clrex
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; CHECK-THUMBV7-NEXT: bx lr
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