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llvm-mirror/test/Transforms/IndVarSimplify/full_widening.ll
Roman Lebedev f3dbbac126 [SCEV] SCEVExpander::isHighCostExpansionHelper(): cost-model min/max (PR44668)
Summary:
Previosly we simply always said that `SCEVMinMaxExpr` is too costly to expand.
But this isn't really true, it expands into just a comparison+swap pair.
And again much like with add/mul, there will be one less such pair
than the number of operands. And we need to count the cost of operands themselves.

This does change a number of testcases, and as far as i can tell,
all of these changes are improvements, in the sense that
we fixed up more latches to do the [in]equality comparison.

This concludes cost-modelling changes, no other SCEV expressions exist as of now.

This is a part of addressing [[ https://bugs.llvm.org/show_bug.cgi?id=44668 | PR44668 ]].

Reviewers: reames, mkazantsev, wmi, sanjoy

Reviewed By: mkazantsev

Subscribers: hiraditya, javed.absar, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D73744
2020-02-25 23:05:59 +03:00

47 lines
2.2 KiB
LLVM

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -indvars -S | FileCheck %s
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-n8:16:32:64"
; Make sure that we do not insert trunc in the loop.
define i32 @test_01(double* %p, double %x, i32* %np, i32* %mp, i32 %k) {
; CHECK-LABEL: @test_01(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP0:%.*]] = icmp sgt i32 [[K:%.*]], 1
; CHECK-NEXT: [[SMAX:%.*]] = select i1 [[TMP0]], i32 [[K]], i32 1
; CHECK-NEXT: [[WIDE_TRIP_COUNT:%.*]] = zext i32 [[SMAX]] to i64
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: [[IV_WIDE:%.*]] = phi i64 [ [[CANONICAL_IV_NEXT_I:%.*]], [[LOOP]] ], [ 0, [[ENTRY:%.*]] ]
; CHECK-NEXT: [[CANONICAL_IV_NEXT_I]] = add nuw nsw i64 [[IV_WIDE]], 1
; CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds double, double* [[P:%.*]], i64 [[IV_WIDE]]
; CHECK-NEXT: [[LOAD:%.*]] = load atomic double, double* [[GEP]] unordered, align 8
; CHECK-NEXT: [[MUL:%.*]] = fmul double [[X:%.*]], [[LOAD]]
; CHECK-NEXT: [[GEP2:%.*]] = getelementptr inbounds double, double* [[P]], i64 [[IV_WIDE]]
; CHECK-NEXT: store atomic double [[MUL]], double* [[GEP2]] unordered, align 8
; CHECK-NEXT: [[EXITCOND:%.*]] = icmp ne i64 [[CANONICAL_IV_NEXT_I]], [[WIDE_TRIP_COUNT]]
; CHECK-NEXT: br i1 [[EXITCOND]], label [[LOOP]], label [[EXIT:%.*]]
; CHECK: exit:
; CHECK-NEXT: ret i32 0
;
entry:
br label %loop
loop:
%iv.wide = phi i64 [ %canonical.iv.next.i, %loop ], [ 0, %entry ]
%iv.narrow = phi i32 [ %iv.narrow.next, %loop ], [ 0, %entry ]
%canonical.iv.next.i = add nuw nsw i64 %iv.wide, 1
%zext = zext i32 %iv.narrow to i64
%gep = getelementptr inbounds double, double* %p, i64 %zext
%load = load atomic double, double* %gep unordered, align 8
%mul = fmul double %x, %load
%gep2 = getelementptr inbounds double, double* %p, i64 %zext
store atomic double %mul, double* %gep2 unordered, align 8
%iv.narrow.next = add nuw nsw i32 %iv.narrow, 1
%loop.cond = icmp slt i32 %iv.narrow.next, %k
br i1 %loop.cond, label %loop, label %exit
exit:
ret i32 0
}