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llvm-project/llvm/test/CodeGen/Thumb2/v8_IT_5.ll

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ARM & AArch64: make use of common cmpxchg idioms after expansion 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 llvm-svn: 209883
2014-05-30 18:09:59 +08:00
; RUN: llc < %s -mtriple=thumbv8 -arm-atomic-cfg-tidy=0 | FileCheck %s
; RUN: llc < %s -mtriple=thumbv7 -arm-atomic-cfg-tidy=0 -arm-restrict-it | FileCheck %s
[Dominators] Include infinite loops in PostDominatorTree Summary: This patch teaches PostDominatorTree about infinite loops. It is built on top of D29705 by @dberlin which includes a very detailed motivation for this change. What's new is that the patch also teaches the incremental updater how to deal with reverse-unreachable regions and how to properly maintain and verify tree roots. Before that, the incremental algorithm sometimes ended up preserving reverse-unreachable regions after updates that wouldn't appear in the tree if it was constructed from scratch on the same CFG. This patch makes the following assumptions: - A sequence of updates should produce the same tree as a recalculating it. - Any sequence of the same updates should lead to the same tree. - Siblings and roots are unordered. The last two properties are essential to efficiently perform batch updates in the future. When it comes to the first one, we can decide later that the consistency between freshly built tree and an updated one doesn't matter match, as there are many correct ways to pick roots in infinite loops, and to relax this assumption. That should enable us to recalculate postdominators less frequently. This patch is pretty conservative when it comes to incremental updates on reverse-unreachable regions and ends up recalculating the whole tree in many cases. It should be possible to improve the performance in many cases, if we decide that it's important enough. That being said, my experiments showed that reverse-unreachable are very rare in the IR emitted by clang when bootstrapping clang. Here are the statistics I collected by analyzing IR between passes and after each removePredecessor call: ``` # functions: 52283 # samples: 337609 # reverse unreachable BBs: 216022 # BBs: 247840796 Percent reverse-unreachable: 0.08716159869015269 % Max(PercRevUnreachable) in a function: 87.58620689655172 % # > 25 % samples: 471 ( 0.1395104988314885 % samples ) ... in 145 ( 0.27733680163724345 % functions ) ``` Most of the reverse-unreachable regions come from invalid IR where it wouldn't be possible to construct a PostDomTree anyway. I would like to commit this patch in the next week in order to be able to complete the work that depends on it before the end of my internship, so please don't wait long to voice your concerns :). Reviewers: dberlin, sanjoy, grosser, brzycki, davide, chandlerc, hfinkel Reviewed By: dberlin Subscribers: nhaehnle, javed.absar, kparzysz, uabelho, jlebar, hiraditya, llvm-commits, dberlin, david2050 Differential Revision: https://reviews.llvm.org/D35851 llvm-svn: 310940
2017-08-16 02:14:57 +08:00
; CHECK: it ne
[ARMv8] Prevent generation of deprecated IT blocks on ARMv8 in Thumb mode. IT blocks can only be one instruction lonf, and can only contain a subset of the 16 instructions. Patch by Artyom Skrobov! llvm-svn: 190309
2013-09-09 22:21:49 +08:00
; CHECK-NEXT: cmpne
PGO branch weight: update edge weights in IfConverter. This commit only handles IfConvertTriangle. To update edge weights of a successor, one interface is added to MachineBasicBlock: /// Set successor weight of a given iterator. setSuccWeight(succ_iterator I, uint32_t weight) An existing testing case test/CodeGen/Thumb2/v8_IT_5.ll is updated, since we now correctly update the edge weights, the cold block is placed at the end of the function and we jump to the cold block. llvm-svn: 200428
2014-01-30 07:18:47 +08:00
; CHECK-NEXT: bne [[JUMPTARGET:.LBB[0-9]+_[0-9]+]]
ARM: When re-creating a branch via InsertBranch, preserve CPSR flags. In particular, this preserves the kill flag, which allows the Thumb2 cbn?z optimization to be applied in cases where a branch has been re-created after the live variables analysis pass, e.g. by the machine block placement pass. This appears to be low risk; a number of other targets seem to already be doing something similar, e.g. AArch64, PowerPC. Differential Revision: http://reviews.llvm.org/D9184 llvm-svn: 235639
2015-04-24 04:31:32 +08:00
; CHECK: cbz
[ARMv8] Prevent generation of deprecated IT blocks on ARMv8 in Thumb mode. IT blocks can only be one instruction lonf, and can only contain a subset of the 16 instructions. Patch by Artyom Skrobov! llvm-svn: 190309
2013-09-09 22:21:49 +08:00
; CHECK-NEXT: %if.else163
; CHECK-NEXT: mov.w
; CHECK-NEXT: b
Distribute the weight on the edge from switch to default statement to edges generated in lowering switch. Currently, when edge weights are assigned to edges that are created when lowering switch statement, the weight on the edge to default statement (let's call it "default weight" here) is not considered. We need to distribute this weight properly. However, without value profiling, we have no idea how to distribute it. In this patch, I applied the heuristic that this weight is evenly distributed to successors. For example, given a switch statement with cases 1,2,3,5,10,11,20, and every edge from switch to each successor has weight 10. If there is a binary search tree built to test if n < 10, then its two out-edges will have weight 4x10+10/2 = 45 and 3x10 + 10/2 = 35 respectively (currently they are 40 and 30 without considering the default weight). Each distribution (which is 5 here) will be stored in each SwitchWorkListItem for further distribution. There are some exceptions: For a jump table header which doesn't have any edge to default statement, we don't distribute the default weight to it. For a bit test header which covers a contiguous range and hence has no edges to default statement, we don't distribute the default weight to it. When the branch checks a single value or a contiguous range with no edge to default statement, we don't distribute the default weight to it. In other cases, the default weight is evenly distributed to successors. Differential Revision: http://reviews.llvm.org/D12418 llvm-svn: 246522
2015-09-01 09:42:16 +08:00
; CHECK: [[JUMPTARGET]]:{{.*}}%if.else173
; CHECK-NEXT: mov.w
[Dominators] Include infinite loops in PostDominatorTree Summary: This patch teaches PostDominatorTree about infinite loops. It is built on top of D29705 by @dberlin which includes a very detailed motivation for this change. What's new is that the patch also teaches the incremental updater how to deal with reverse-unreachable regions and how to properly maintain and verify tree roots. Before that, the incremental algorithm sometimes ended up preserving reverse-unreachable regions after updates that wouldn't appear in the tree if it was constructed from scratch on the same CFG. This patch makes the following assumptions: - A sequence of updates should produce the same tree as a recalculating it. - Any sequence of the same updates should lead to the same tree. - Siblings and roots are unordered. The last two properties are essential to efficiently perform batch updates in the future. When it comes to the first one, we can decide later that the consistency between freshly built tree and an updated one doesn't matter match, as there are many correct ways to pick roots in infinite loops, and to relax this assumption. That should enable us to recalculate postdominators less frequently. This patch is pretty conservative when it comes to incremental updates on reverse-unreachable regions and ends up recalculating the whole tree in many cases. It should be possible to improve the performance in many cases, if we decide that it's important enough. That being said, my experiments showed that reverse-unreachable are very rare in the IR emitted by clang when bootstrapping clang. Here are the statistics I collected by analyzing IR between passes and after each removePredecessor call: ``` # functions: 52283 # samples: 337609 # reverse unreachable BBs: 216022 # BBs: 247840796 Percent reverse-unreachable: 0.08716159869015269 % Max(PercRevUnreachable) in a function: 87.58620689655172 % # > 25 % samples: 471 ( 0.1395104988314885 % samples ) ... in 145 ( 0.27733680163724345 % functions ) ``` Most of the reverse-unreachable regions come from invalid IR where it wouldn't be possible to construct a PostDomTree anyway. I would like to commit this patch in the next week in order to be able to complete the work that depends on it before the end of my internship, so please don't wait long to voice your concerns :). Reviewers: dberlin, sanjoy, grosser, brzycki, davide, chandlerc, hfinkel Reviewed By: dberlin Subscribers: nhaehnle, javed.absar, kparzysz, uabelho, jlebar, hiraditya, llvm-commits, dberlin, david2050 Differential Revision: https://reviews.llvm.org/D35851 llvm-svn: 310940
2017-08-16 02:14:57 +08:00
; CHECK-NEXT: bx lr
; CHECK: %if.else145
[ARMv8] Prevent generation of deprecated IT blocks on ARMv8 in Thumb mode. IT blocks can only be one instruction lonf, and can only contain a subset of the 16 instructions. Patch by Artyom Skrobov! llvm-svn: 190309
2013-09-09 22:21:49 +08:00
; CHECK-NEXT: mov.w
[Dominators] Include infinite loops in PostDominatorTree Summary: This patch teaches PostDominatorTree about infinite loops. It is built on top of D29705 by @dberlin which includes a very detailed motivation for this change. What's new is that the patch also teaches the incremental updater how to deal with reverse-unreachable regions and how to properly maintain and verify tree roots. Before that, the incremental algorithm sometimes ended up preserving reverse-unreachable regions after updates that wouldn't appear in the tree if it was constructed from scratch on the same CFG. This patch makes the following assumptions: - A sequence of updates should produce the same tree as a recalculating it. - Any sequence of the same updates should lead to the same tree. - Siblings and roots are unordered. The last two properties are essential to efficiently perform batch updates in the future. When it comes to the first one, we can decide later that the consistency between freshly built tree and an updated one doesn't matter match, as there are many correct ways to pick roots in infinite loops, and to relax this assumption. That should enable us to recalculate postdominators less frequently. This patch is pretty conservative when it comes to incremental updates on reverse-unreachable regions and ends up recalculating the whole tree in many cases. It should be possible to improve the performance in many cases, if we decide that it's important enough. That being said, my experiments showed that reverse-unreachable are very rare in the IR emitted by clang when bootstrapping clang. Here are the statistics I collected by analyzing IR between passes and after each removePredecessor call: ``` # functions: 52283 # samples: 337609 # reverse unreachable BBs: 216022 # BBs: 247840796 Percent reverse-unreachable: 0.08716159869015269 % Max(PercRevUnreachable) in a function: 87.58620689655172 % # > 25 % samples: 471 ( 0.1395104988314885 % samples ) ... in 145 ( 0.27733680163724345 % functions ) ``` Most of the reverse-unreachable regions come from invalid IR where it wouldn't be possible to construct a PostDomTree anyway. I would like to commit this patch in the next week in order to be able to complete the work that depends on it before the end of my internship, so please don't wait long to voice your concerns :). Reviewers: dberlin, sanjoy, grosser, brzycki, davide, chandlerc, hfinkel Reviewed By: dberlin Subscribers: nhaehnle, javed.absar, kparzysz, uabelho, jlebar, hiraditya, llvm-commits, dberlin, david2050 Differential Revision: https://reviews.llvm.org/D35851 llvm-svn: 310940
2017-08-16 02:14:57 +08:00
; CHECK: pop.w
[ARMv8] Prevent generation of deprecated IT blocks on ARMv8 in Thumb mode. IT blocks can only be one instruction lonf, and can only contain a subset of the 16 instructions. Patch by Artyom Skrobov! llvm-svn: 190309
2013-09-09 22:21:49 +08:00
%struct.hc = type { i32, i32, i32, i32 }
define i32 @t(i32 %type) optsize {
entry:
switch i32 %type, label %if.else173 [
Codegen: Fix broken assumption in Tail Merge. Tail merge was making the assumption that a layout successor or predecessor was always a cfg successor/predecessor. Remove that assumption. Changes to tests are necessary because the errant cfg edges were preventing optimizations. llvm-svn: 273700
2016-06-25 02:16:36 +08:00
i32 13, label %if.then115
i32 6, label %if.then102
[ARMv8] Prevent generation of deprecated IT blocks on ARMv8 in Thumb mode. IT blocks can only be one instruction lonf, and can only contain a subset of the 16 instructions. Patch by Artyom Skrobov! llvm-svn: 190309
2013-09-09 22:21:49 +08:00
]
if.then102:
Codegen: Fix broken assumption in Tail Merge. Tail merge was making the assumption that a layout successor or predecessor was always a cfg successor/predecessor. Remove that assumption. Changes to tests are necessary because the errant cfg edges were preventing optimizations. llvm-svn: 273700
2016-06-25 02:16:36 +08:00
br label %if.then115
[ARMv8] Prevent generation of deprecated IT blocks on ARMv8 in Thumb mode. IT blocks can only be one instruction lonf, and can only contain a subset of the 16 instructions. Patch by Artyom Skrobov! llvm-svn: 190309
2013-09-09 22:21:49 +08:00
if.then115:
br i1 undef, label %if.else163, label %if.else145
if.else145:
%call150 = call fastcc %struct.hc* @foo(%struct.hc* undef, i32 34865152) optsize
br label %while.body172
if.else163:
%call168 = call fastcc %struct.hc* @foo(%struct.hc* undef, i32 34078720) optsize
br label %while.body172
while.body172:
br label %while.body172
if.else173:
ret i32 -1
}
declare hidden fastcc %struct.hc* @foo(%struct.hc* nocapture, i32) nounwind optsize