87fdcb8749
This way it will be more obvious that the problem is both in cost threshold and in hardcoded benefit check, plus will show how the instsimplify cleans this all in the end. llvm-svn: 366800
41 lines
1.8 KiB
LLVM
41 lines
1.8 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt < %s -simplifycfg -S | FileCheck %s --check-prefixes=ALL,DEFAULT,FALLBACK0
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; RUN: opt < %s -simplifycfg -phi-node-folding-threshold=2 -S | FileCheck %s --check-prefixes=ALL,DEFAULT,FALLBACK1
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; RUN: opt < %s -simplifycfg -phi-node-folding-threshold=3 -S | FileCheck %s --check-prefixes=ALL,COSTLY
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; This is checking that the multiplication does overflow, with a leftover
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; guard against division-by-zero that was needed before InstCombine
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; produced llvm.umul.with.overflow.
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define i1 @will_overflow(i64 %size, i64 %nmemb) {
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; ALL-LABEL: @will_overflow(
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; ALL-NEXT: entry:
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; ALL-NEXT: [[CMP:%.*]] = icmp eq i64 [[SIZE:%.*]], 0
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; ALL-NEXT: br i1 [[CMP]], label [[LAND_END:%.*]], label [[LAND_RHS:%.*]]
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; ALL: land.rhs:
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; ALL-NEXT: [[UMUL:%.*]] = tail call { i64, i1 } @llvm.umul.with.overflow.i64(i64 [[SIZE]], i64 [[NMEMB:%.*]])
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; ALL-NEXT: [[UMUL_OV:%.*]] = extractvalue { i64, i1 } [[UMUL]], 1
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; ALL-NEXT: [[UMUL_NOT_OV:%.*]] = xor i1 [[UMUL_OV]], true
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; ALL-NEXT: br label [[LAND_END]]
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; ALL: land.end:
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; ALL-NEXT: [[TMP0:%.*]] = phi i1 [ true, [[ENTRY:%.*]] ], [ [[UMUL_NOT_OV]], [[LAND_RHS]] ]
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; ALL-NEXT: ret i1 [[TMP0]]
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;
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entry:
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%cmp = icmp eq i64 %size, 0
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br i1 %cmp, label %land.end, label %land.rhs
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land.rhs: ; preds = %entry
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%umul = tail call { i64, i1 } @llvm.umul.with.overflow.i64(i64 %size, i64 %nmemb)
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%umul.ov = extractvalue { i64, i1 } %umul, 1
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%umul.not.ov = xor i1 %umul.ov, true
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br label %land.end
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land.end: ; preds = %land.rhs, %entry
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%0 = phi i1 [ true, %entry ], [ %umul.not.ov, %land.rhs ]
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ret i1 %0
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}
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; Function Attrs: nounwind readnone speculatable
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declare { i64, i1 } @llvm.umul.with.overflow.i64(i64, i64) #0
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