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llvm-project/llvm/test/Transforms/LoopSimplify/merge-exits.ll
Matthias Braun 5d7f84ee17 LoopRotate: Add code to update branch weights 
This adds code to the loop rotation transformation to ensure that the
computed block execution counts for the loop bodies are the same before
and after the transformation. This isn't always true in practice, but I
believe this is because of numeric inaccuracies in the BlockFrequency
computation.

The invariants this is modeled on and heuristic choice of 0-trip loop
amount is explained in a lenghty comment in the new
`updateBranchWeights()` function.

Differential Revision: https://reviews.llvm.org/D157462
2023-09-11 10:38:06 -07:00

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; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -passes=loop-simplify,loop-rotate,instcombine,indvars -S -verify-loop-info -verify-dom-info | FileCheck %s
; Loopsimplify should be able to merge the two loop exits
; into one, so that loop rotate can rotate the loop, so
; that indvars can promote the induction variable to i64
; without needing casts.
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n32:64"
define float @test1(ptr %pTmp1, ptr %peakWeight, i32 %bandEdgeIndex) nounwind {
; CHECK-LABEL: @test1(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[T0:%.*]] = load float, ptr [[PEAKWEIGHT:%.*]], align 4
; CHECK-NEXT: [[T11:%.*]] = add i32 [[BANDEDGEINDEX:%.*]], -1
; CHECK-NEXT: [[T121:%.*]] = icmp sgt i32 [[T11]], 0
; CHECK-NEXT: br i1 [[T121]], label [[BB_LR_PH:%.*]], label [[BB3:%.*]]
; CHECK: bb.lr.ph:
; CHECK-NEXT: [[TMP0:%.*]] = sext i32 [[T11]] to i64
; CHECK-NEXT: br label [[BB:%.*]]
; CHECK: bb:
; CHECK-NEXT: [[INDVARS_IV:%.*]] = phi i64 [ 0, [[BB_LR_PH]] ], [ [[INDVARS_IV_NEXT:%.*]], [[BB]] ]
; CHECK-NEXT: [[DISTERBHI_04:%.*]] = phi float [ 0.000000e+00, [[BB_LR_PH]] ], [ [[T4:%.*]], [[BB]] ]
; CHECK-NEXT: [[PEAKCOUNT_02:%.*]] = phi float [ [[T0]], [[BB_LR_PH]] ], [ [[T9:%.*]], [[BB]] ]
; CHECK-NEXT: [[T2:%.*]] = getelementptr float, ptr [[PTMP1:%.*]], i64 [[INDVARS_IV]]
; CHECK-NEXT: [[T3:%.*]] = load float, ptr [[T2]], align 4
; CHECK-NEXT: [[T4]] = fadd float [[T3]], [[DISTERBHI_04]]
; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add nuw nsw i64 [[INDVARS_IV]], 1
; CHECK-NEXT: [[T7:%.*]] = getelementptr float, ptr [[PEAKWEIGHT]], i64 [[INDVARS_IV_NEXT]]
; CHECK-NEXT: [[T8:%.*]] = load float, ptr [[T7]], align 4
; CHECK-NEXT: [[T9]] = fadd float [[T8]], [[PEAKCOUNT_02]]
; CHECK-NEXT: [[T10:%.*]] = fcmp olt float [[T4]], 2.500000e+00
; CHECK-NEXT: [[T12:%.*]] = icmp sgt i64 [[TMP0]], [[INDVARS_IV_NEXT]]
; CHECK-NEXT: [[OR_COND:%.*]] = and i1 [[T10]], [[T12]]
; CHECK-NEXT: br i1 [[OR_COND]], label [[BB]], label [[BB1_BB3_CRIT_EDGE:%.*]]
; CHECK: bb1.bb3_crit_edge:
; CHECK-NEXT: [[T4_LCSSA:%.*]] = phi float [ [[T4]], [[BB]] ]
; CHECK-NEXT: [[T9_LCSSA:%.*]] = phi float [ [[T9]], [[BB]] ]
; CHECK-NEXT: br label [[BB3]]
; CHECK: bb3:
; CHECK-NEXT: [[PEAKCOUNT_0_LCSSA:%.*]] = phi float [ [[T9_LCSSA]], [[BB1_BB3_CRIT_EDGE]] ], [ [[T0]], [[ENTRY:%.*]] ]
; CHECK-NEXT: [[DISTERBHI_0_LCSSA:%.*]] = phi float [ [[T4_LCSSA]], [[BB1_BB3_CRIT_EDGE]] ], [ 0.000000e+00, [[ENTRY]] ]
; CHECK-NEXT: [[T13:%.*]] = fdiv float [[PEAKCOUNT_0_LCSSA]], [[DISTERBHI_0_LCSSA]]
; CHECK-NEXT: ret float [[T13]]
;
entry:
%t0 = load float, ptr %peakWeight, align 4
br label %bb1
bb: ; preds = %bb2
%t1 = sext i32 %hiPart.0 to i64
%t2 = getelementptr float, ptr %pTmp1, i64 %t1
%t3 = load float, ptr %t2, align 4
%t4 = fadd float %t3, %distERBhi.0
%t5 = add i32 %hiPart.0, 1
%t6 = sext i32 %t5 to i64
%t7 = getelementptr float, ptr %peakWeight, i64 %t6
%t8 = load float, ptr %t7, align 4
%t9 = fadd float %t8, %peakCount.0
br label %bb1
bb1: ; preds = %bb, %entry
%peakCount.0 = phi float [ %t0, %entry ], [ %t9, %bb ]
%hiPart.0 = phi i32 [ 0, %entry ], [ %t5, %bb ]
%distERBhi.0 = phi float [ 0.000000e+00, %entry ], [ %t4, %bb ]
%t10 = fcmp uge float %distERBhi.0, 2.500000e+00
br i1 %t10, label %bb3, label %bb2
bb2: ; preds = %bb1
%t11 = add i32 %bandEdgeIndex, -1
%t12 = icmp sgt i32 %t11, %hiPart.0
br i1 %t12, label %bb, label %bb3
bb3: ; preds = %bb2, %bb1
%t13 = fdiv float %peakCount.0, %distERBhi.0
ret float %t13
}
; Same test as above.
; This would crash because we assumed TTI was available to process the metadata.
define float @merge_branches_profile_metadata(ptr %pTmp1, ptr %peakWeight, i32 %bandEdgeIndex) nounwind {
; CHECK-LABEL: @merge_branches_profile_metadata(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[T0:%.*]] = load float, ptr [[PEAKWEIGHT:%.*]], align 4
; CHECK-NEXT: [[T11:%.*]] = add i32 [[BANDEDGEINDEX:%.*]], -1
; CHECK-NEXT: [[T121:%.*]] = icmp sgt i32 [[T11]], 0
; CHECK-NEXT: br i1 [[T121]], label [[BB_LR_PH:%.*]], label [[BB3:%.*]], !prof [[PROF0:![0-9]+]]
; CHECK: bb.lr.ph:
; CHECK-NEXT: [[TMP0:%.*]] = sext i32 [[T11]] to i64
; CHECK-NEXT: br label [[BB:%.*]]
; CHECK: bb:
; CHECK-NEXT: [[INDVARS_IV:%.*]] = phi i64 [ 0, [[BB_LR_PH]] ], [ [[INDVARS_IV_NEXT:%.*]], [[BB]] ]
; CHECK-NEXT: [[DISTERBHI_04:%.*]] = phi float [ 0.000000e+00, [[BB_LR_PH]] ], [ [[T4:%.*]], [[BB]] ]
; CHECK-NEXT: [[PEAKCOUNT_02:%.*]] = phi float [ [[T0]], [[BB_LR_PH]] ], [ [[T9:%.*]], [[BB]] ]
; CHECK-NEXT: [[T2:%.*]] = getelementptr float, ptr [[PTMP1:%.*]], i64 [[INDVARS_IV]]
; CHECK-NEXT: [[T3:%.*]] = load float, ptr [[T2]], align 4
; CHECK-NEXT: [[T4]] = fadd float [[T3]], [[DISTERBHI_04]]
; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add nuw nsw i64 [[INDVARS_IV]], 1
; CHECK-NEXT: [[T7:%.*]] = getelementptr float, ptr [[PEAKWEIGHT]], i64 [[INDVARS_IV_NEXT]]
; CHECK-NEXT: [[T8:%.*]] = load float, ptr [[T7]], align 4
; CHECK-NEXT: [[T9]] = fadd float [[T8]], [[PEAKCOUNT_02]]
; CHECK-NEXT: [[T10:%.*]] = fcmp olt float [[T4]], 2.500000e+00
; CHECK-NEXT: [[T12:%.*]] = icmp sgt i64 [[TMP0]], [[INDVARS_IV_NEXT]]
; CHECK-NEXT: [[OR_COND:%.*]] = and i1 [[T10]], [[T12]]
; CHECK-NEXT: br i1 [[OR_COND]], label [[BB]], label [[BB1_BB3_CRIT_EDGE:%.*]], !prof [[PROF1:![0-9]+]]
; CHECK: bb1.bb3_crit_edge:
; CHECK-NEXT: [[T4_LCSSA:%.*]] = phi float [ [[T4]], [[BB]] ]
; CHECK-NEXT: [[T9_LCSSA:%.*]] = phi float [ [[T9]], [[BB]] ]
; CHECK-NEXT: br label [[BB3]]
; CHECK: bb3:
; CHECK-NEXT: [[PEAKCOUNT_0_LCSSA:%.*]] = phi float [ [[T9_LCSSA]], [[BB1_BB3_CRIT_EDGE]] ], [ [[T0]], [[ENTRY:%.*]] ]
; CHECK-NEXT: [[DISTERBHI_0_LCSSA:%.*]] = phi float [ [[T4_LCSSA]], [[BB1_BB3_CRIT_EDGE]] ], [ 0.000000e+00, [[ENTRY]] ]
; CHECK-NEXT: [[T13:%.*]] = fdiv float [[PEAKCOUNT_0_LCSSA]], [[DISTERBHI_0_LCSSA]]
; CHECK-NEXT: ret float [[T13]]
;
entry:
%t0 = load float, ptr %peakWeight, align 4
br label %bb1
bb: ; preds = %bb2
%t1 = sext i32 %hiPart.0 to i64
%t2 = getelementptr float, ptr %pTmp1, i64 %t1
%t3 = load float, ptr %t2, align 4
%t4 = fadd float %t3, %distERBhi.0
%t5 = add i32 %hiPart.0, 1
%t6 = sext i32 %t5 to i64
%t7 = getelementptr float, ptr %peakWeight, i64 %t6
%t8 = load float, ptr %t7, align 4
%t9 = fadd float %t8, %peakCount.0
br label %bb1
bb1: ; preds = %bb, %entry
%peakCount.0 = phi float [ %t0, %entry ], [ %t9, %bb ]
%hiPart.0 = phi i32 [ 0, %entry ], [ %t5, %bb ]
%distERBhi.0 = phi float [ 0.000000e+00, %entry ], [ %t4, %bb ]
%t10 = fcmp uge float %distERBhi.0, 2.500000e+00
br i1 %t10, label %bb3, label %bb2, !prof !0
bb2: ; preds = %bb1
%t11 = add i32 %bandEdgeIndex, -1
%t12 = icmp sgt i32 %t11, %hiPart.0
br i1 %t12, label %bb, label %bb3
bb3: ; preds = %bb2, %bb1
%t13 = fdiv float %peakCount.0, %distERBhi.0
ret float %t13
}
!0 = !{!"branch_weights", i32 2000, i32 1}
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