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llvm-project/llvm/test/CodeGen/X86/phys_subreg_coalesce-2.ll

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Prepare remaining tests for -join-physreg going away. llvm-svn: 130893
2011-05-05 07:54:59 +08:00
; RUN: llc < %s -march=x86 | FileCheck %s
[RegisterCoalescer] Add a rule to consider more profitable copies first when those are in the same basic block. The previous approach was the topological order of the basic block. By default this rule is disabled. Related to PR22768. llvm-svn: 233241
2015-03-26 09:01:48 +08:00
; RUN: llc -no-phi-elim-live-out-early-exit -terminal-rule < %s -march=x86 | FileCheck %s
Add test case from PR2659. llvm-svn: 62006
2009-01-10 05:01:31 +08:00
; PR2659
define i32 @binomial(i32 %n, i32 %k) nounwind {
entry:
%cmp = icmp ugt i32 %k, %n ; <i1> [#uses=1]
br i1 %cmp, label %ifthen, label %forcond.preheader
forcond.preheader: ; preds = %entry
%cmp44 = icmp eq i32 %k, 0 ; <i1> [#uses=1]
br i1 %cmp44, label %afterfor, label %forbody
ifthen: ; preds = %entry
ret i32 0
Don't delete empty preheaders in CodeGenPrepare if it would create a critical edge Presently, CodeGenPrepare deletes all nearly empty (only phi and branch) basic blocks. This pass can delete loop preheaders which frequently creates critical edges. A preheader can be a convenient place to spill registers to the stack. If the entrance to a loop body is a critical edge, then spills may occur in the loop body rather than immediately before it. This patch protects loop preheaders from deletion in CodeGenPrepare even if they are nearly empty. Since the patch alters the CFG, it affects a large number of test cases. In most cases, the changes are merely cosmetic (basic blocks have different names or instruction orders change slightly). I am somewhat concerned about the test/CodeGen/Mips/brdelayslot.ll test case. If the loop preheader is not deleted, then the MIPS backend does not take advantage of a branch delay slot. Consequently, I would like some close review by a MIPS expert. The patch also partially subsumes D16893 from George Burgess IV. George correctly notes that CodeGenPrepare does not actually preserve the dominator tree. I think the dominator tree was usually not valid when CodeGenPrepare ran, but I am using LoopInfo to mark preheaders, so the dominator tree is now always valid before CodeGenPrepare. Author: Tom Jablin (tjablin) Reviewers: hfinkel george.burgess.iv vkalintiris dsanders kbarton cycheng http://reviews.llvm.org/D16984 llvm-svn: 265397
2016-04-05 22:06:20 +08:00
; CHECK: forbody{{$}}
Using branch probability to guide critical edge splitting. Summary: The original heuristic to break critical edge during machine sink is relatively conservertive: when there is only one instruction sinkable to the critical edge, it is likely that the machine sink pass will not break the critical edge. This leads to many speculative instructions executed at runtime. However, with profile info, we could model the splitting benefits: if the critical edge has 50% taken rate, it would always be beneficial to split the critical edge to avoid the speculated runtime instructions. This patch uses profile to guide critical edge splitting in machine sink pass. The performance impact on speccpu2006 on Intel sandybridge machines: spec/2006/fp/C++/444.namd 25.3 +0.26% spec/2006/fp/C++/447.dealII 45.96 -0.10% spec/2006/fp/C++/450.soplex 41.97 +1.49% spec/2006/fp/C++/453.povray 36.83 -0.96% spec/2006/fp/C/433.milc 23.81 +0.32% spec/2006/fp/C/470.lbm 41.17 +0.34% spec/2006/fp/C/482.sphinx3 48.13 +0.69% spec/2006/int/C++/471.omnetpp 22.45 +3.25% spec/2006/int/C++/473.astar 21.35 -2.06% spec/2006/int/C++/483.xalancbmk 36.02 -2.39% spec/2006/int/C/400.perlbench 33.7 -0.17% spec/2006/int/C/401.bzip2 22.9 +0.52% spec/2006/int/C/403.gcc 32.42 -0.54% spec/2006/int/C/429.mcf 39.59 +0.19% spec/2006/int/C/445.gobmk 26.98 -0.00% spec/2006/int/C/456.hmmer 24.52 -0.18% spec/2006/int/C/458.sjeng 28.26 +0.02% spec/2006/int/C/462.libquantum 55.44 +3.74% spec/2006/int/C/464.h264ref 46.67 -0.39% geometric mean +0.20% Manually checked 473 and 471 to verify the diff is in the noise range. Reviewers: rengolin, davidxl Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D24818 llvm-svn: 284757
2016-10-21 02:06:52 +08:00
; There should be no mov instruction in the for body.
Prepare remaining tests for -join-physreg going away. llvm-svn: 130893
2011-05-05 07:54:59 +08:00
; CHECK-NOT: mov
Using branch probability to guide critical edge splitting. Summary: The original heuristic to break critical edge during machine sink is relatively conservertive: when there is only one instruction sinkable to the critical edge, it is likely that the machine sink pass will not break the critical edge. This leads to many speculative instructions executed at runtime. However, with profile info, we could model the splitting benefits: if the critical edge has 50% taken rate, it would always be beneficial to split the critical edge to avoid the speculated runtime instructions. This patch uses profile to guide critical edge splitting in machine sink pass. The performance impact on speccpu2006 on Intel sandybridge machines: spec/2006/fp/C++/444.namd 25.3 +0.26% spec/2006/fp/C++/447.dealII 45.96 -0.10% spec/2006/fp/C++/450.soplex 41.97 +1.49% spec/2006/fp/C++/453.povray 36.83 -0.96% spec/2006/fp/C/433.milc 23.81 +0.32% spec/2006/fp/C/470.lbm 41.17 +0.34% spec/2006/fp/C/482.sphinx3 48.13 +0.69% spec/2006/int/C++/471.omnetpp 22.45 +3.25% spec/2006/int/C++/473.astar 21.35 -2.06% spec/2006/int/C++/483.xalancbmk 36.02 -2.39% spec/2006/int/C/400.perlbench 33.7 -0.17% spec/2006/int/C/401.bzip2 22.9 +0.52% spec/2006/int/C/403.gcc 32.42 -0.54% spec/2006/int/C/429.mcf 39.59 +0.19% spec/2006/int/C/445.gobmk 26.98 -0.00% spec/2006/int/C/456.hmmer 24.52 -0.18% spec/2006/int/C/458.sjeng 28.26 +0.02% spec/2006/int/C/462.libquantum 55.44 +3.74% spec/2006/int/C/464.h264ref 46.67 -0.39% geometric mean +0.20% Manually checked 473 and 471 to verify the diff is in the noise range. Reviewers: rengolin, davidxl Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D24818 llvm-svn: 284757
2016-10-21 02:06:52 +08:00
; CHECK: jbe
Add test case from PR2659. llvm-svn: 62006
2009-01-10 05:01:31 +08:00
forbody: ; preds = %forbody, %forcond.preheader
%indvar = phi i32 [ 0, %forcond.preheader ], [ %divisor.02, %forbody ] ; <i32> [#uses=3]
%accumulator.01 = phi i32 [ 1, %forcond.preheader ], [ %div, %forbody ] ; <i32> [#uses=1]
%divisor.02 = add i32 %indvar, 1 ; <i32> [#uses=2]
%n.addr.03 = sub i32 %n, %indvar ; <i32> [#uses=1]
%mul = mul i32 %n.addr.03, %accumulator.01 ; <i32> [#uses=1]
%div = udiv i32 %mul, %divisor.02 ; <i32> [#uses=2]
%inc = add i32 %indvar, 2 ; <i32> [#uses=1]
%cmp4 = icmp ugt i32 %inc, %k ; <i1> [#uses=1]
br i1 %cmp4, label %afterfor, label %forbody
afterfor: ; preds = %forbody, %forcond.preheader
%accumulator.0.lcssa = phi i32 [ 1, %forcond.preheader ], [ %div, %forbody ] ; <i32> [#uses=1]
ret i32 %accumulator.0.lcssa
}