b3b993a7ad
This reverts the revert commit 408c4408fa.
This version of the patch includes a fix for a crash caused by
treating ICmp/FCmp constant expressions as instructions.
Original message:
On some targets, like AArch64, vector selects can be efficiently lowered
if the vector condition is a compare with a supported predicate.
This patch adds a new argument to getCmpSelInstrCost, to indicate the
predicate of the feeding select condition. Note that it is not
sufficient to use the context instruction when querying the cost of a
vector select starting from a scalar one, because the condition of the
vector select could be composed of compares with different predicates.
This change greatly improves modeling the costs of certain
compare/select patterns on AArch64.
I am also planning on putting up patches to make use of the new argument in
SLPVectorizer & LV.
24 lines
827 B
LLVM
24 lines
827 B
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt -simplifycfg -S %s | FileCheck %s
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@glob = internal constant [5 x i8*] zeroinitializer, align 16
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; Make sure simplifycfg does not crash when dealing with icmp constant
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; expressions.
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define i1 @test(i1 %c) {
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; CHECK-LABEL: @test(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[C:%.*]], i1 false, i1 icmp ult (i8** getelementptr inbounds ([5 x i8*], [5 x i8*]* @glob, i64 0, i64 0), i8** inttoptr (i64 -40 to i8**))
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; CHECK-NEXT: ret i1 [[SPEC_SELECT]]
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;
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entry:
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br i1 %c, label %if.then, label %exit
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if.then:
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br label %exit
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exit:
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%p = phi i1 [ false, %if.then ], [ icmp ult (i8** getelementptr inbounds ([5 x i8*], [5 x i8*]* @glob, i64 0, i64 0), i8** inttoptr (i64 -40 to i8**)), %entry ]
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ret i1 %p
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}
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