3e8a76abfd
This change was mentioned at least as far back as: https://bugs.llvm.org/show_bug.cgi?id=26837#c26 ...and I found a real program that is harmed by this: Himeno running on AMD Jaguar gets 6% slower with SLP vectorization: https://bugs.llvm.org/show_bug.cgi?id=36280 ...but the change here appears to solve that bug only accidentally. The div/rem costs for x86 look very wrong in some cases, but that's already true, so we can fix those in follow-up patches. There's also evidence that more cost model changes are needed to solve SLP problems as shown in D42981, but that's an independent problem (though the solution may be adjusted after this change is made). Differential Revision: https://reviews.llvm.org/D43079 llvm-svn: 325515
124 lines
4.3 KiB
LLVM
124 lines
4.3 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt -S -loop-vectorize -mtriple=x86_64-apple-darwin %s | FileCheck %s
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; FIXME: The intent is that we should be able to vectorize this on x86
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; because that would be profitable, but the cost model says it is not.
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; Two mostly identical functions. The only difference is the presence of
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; fast-math flags on the second. The loop is a pretty simple reduction:
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; for (int i = 0; i < 32; ++i)
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; if (arr[i] != 42.0)
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; tot += arr[i];
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define double @sumIfScalar(double* nocapture readonly %arr) {
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; CHECK-LABEL: @sumIfScalar(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: br label [[LOOP:%.*]]
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; CHECK: loop:
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; CHECK-NEXT: [[I:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[I_NEXT:%.*]], [[NEXT_ITER:%.*]] ]
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; CHECK-NEXT: [[TOT:%.*]] = phi double [ 0.000000e+00, [[ENTRY]] ], [ [[TOT_NEXT:%.*]], [[NEXT_ITER]] ]
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; CHECK-NEXT: [[ADDR:%.*]] = getelementptr double, double* [[ARR:%.*]], i32 [[I]]
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; CHECK-NEXT: [[NEXTVAL:%.*]] = load double, double* [[ADDR]]
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; CHECK-NEXT: [[TST:%.*]] = fcmp une double [[NEXTVAL]], 4.200000e+01
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; CHECK-NEXT: br i1 [[TST]], label [[DO_ADD:%.*]], label [[NO_ADD:%.*]]
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; CHECK: do.add:
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; CHECK-NEXT: [[TOT_NEW:%.*]] = fadd double [[TOT]], [[NEXTVAL]]
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; CHECK-NEXT: br label [[NEXT_ITER]]
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; CHECK: no.add:
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; CHECK-NEXT: br label [[NEXT_ITER]]
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; CHECK: next.iter:
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; CHECK-NEXT: [[TOT_NEXT]] = phi double [ [[TOT]], [[NO_ADD]] ], [ [[TOT_NEW]], [[DO_ADD]] ]
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; CHECK-NEXT: [[I_NEXT]] = add i32 [[I]], 1
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; CHECK-NEXT: [[AGAIN:%.*]] = icmp ult i32 [[I_NEXT]], 32
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; CHECK-NEXT: br i1 [[AGAIN]], label [[LOOP]], label [[DONE:%.*]]
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; CHECK: done:
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; CHECK-NEXT: [[TOT_NEXT_LCSSA:%.*]] = phi double [ [[TOT_NEXT]], [[NEXT_ITER]] ]
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; CHECK-NEXT: ret double [[TOT_NEXT_LCSSA]]
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;
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entry:
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br label %loop
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loop:
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%i = phi i32 [0, %entry], [%i.next, %next.iter]
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%tot = phi double [0.0, %entry], [%tot.next, %next.iter]
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%addr = getelementptr double, double* %arr, i32 %i
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%nextval = load double, double* %addr
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%tst = fcmp une double %nextval, 42.0
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br i1 %tst, label %do.add, label %no.add
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do.add:
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%tot.new = fadd double %tot, %nextval
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br label %next.iter
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no.add:
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br label %next.iter
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next.iter:
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%tot.next = phi double [%tot, %no.add], [%tot.new, %do.add]
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%i.next = add i32 %i, 1
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%again = icmp ult i32 %i.next, 32
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br i1 %again, label %loop, label %done
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done:
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ret double %tot.next
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}
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define double @sumIfVector(double* nocapture readonly %arr) {
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; CHECK-LABEL: @sumIfVector(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: br label [[LOOP:%.*]]
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; CHECK: loop:
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; CHECK-NEXT: [[I:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[I_NEXT:%.*]], [[NEXT_ITER:%.*]] ]
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; CHECK-NEXT: [[TOT:%.*]] = phi double [ 0.000000e+00, [[ENTRY]] ], [ [[TOT_NEXT:%.*]], [[NEXT_ITER]] ]
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; CHECK-NEXT: [[ADDR:%.*]] = getelementptr double, double* [[ARR:%.*]], i32 [[I]]
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; CHECK-NEXT: [[NEXTVAL:%.*]] = load double, double* [[ADDR]]
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; CHECK-NEXT: [[TST:%.*]] = fcmp fast une double [[NEXTVAL]], 4.200000e+01
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; CHECK-NEXT: br i1 [[TST]], label [[DO_ADD:%.*]], label [[NO_ADD:%.*]]
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; CHECK: do.add:
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; CHECK-NEXT: [[TOT_NEW:%.*]] = fadd fast double [[TOT]], [[NEXTVAL]]
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; CHECK-NEXT: br label [[NEXT_ITER]]
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; CHECK: no.add:
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; CHECK-NEXT: br label [[NEXT_ITER]]
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; CHECK: next.iter:
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; CHECK-NEXT: [[TOT_NEXT]] = phi double [ [[TOT]], [[NO_ADD]] ], [ [[TOT_NEW]], [[DO_ADD]] ]
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; CHECK-NEXT: [[I_NEXT]] = add i32 [[I]], 1
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; CHECK-NEXT: [[AGAIN:%.*]] = icmp ult i32 [[I_NEXT]], 32
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; CHECK-NEXT: br i1 [[AGAIN]], label [[LOOP]], label [[DONE:%.*]]
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; CHECK: done:
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; CHECK-NEXT: [[TOT_NEXT_LCSSA:%.*]] = phi double [ [[TOT_NEXT]], [[NEXT_ITER]] ]
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; CHECK-NEXT: ret double [[TOT_NEXT_LCSSA]]
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;
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entry:
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br label %loop
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loop:
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%i = phi i32 [0, %entry], [%i.next, %next.iter]
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%tot = phi double [0.0, %entry], [%tot.next, %next.iter]
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%addr = getelementptr double, double* %arr, i32 %i
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%nextval = load double, double* %addr
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%tst = fcmp fast une double %nextval, 42.0
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br i1 %tst, label %do.add, label %no.add
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do.add:
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%tot.new = fadd fast double %tot, %nextval
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br label %next.iter
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no.add:
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br label %next.iter
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next.iter:
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%tot.next = phi double [%tot, %no.add], [%tot.new, %do.add]
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%i.next = add i32 %i, 1
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%again = icmp ult i32 %i.next, 32
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br i1 %again, label %loop, label %done
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done:
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ret double %tot.next
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}
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