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1228becf7d
This patch deduces `noundef` attributes for return values. IIUC, a function returns `noundef` values iff all of its return values are guaranteed not to be `undef` or `poison`. Definition of `noundef` from LangRef: ``` noundef This attribute applies to parameters and return values. If the value representation contains any undefined or poison bits, the behavior is undefined. Note that this does not refer to padding introduced by the type’s storage representation. ``` Alive2: https://alive2.llvm.org/ce/z/g8Eis6 Compile-time impact: http://llvm-compile-time-tracker.com/compare.php?from=30dcc33c4ea3ab50397a7adbe85fe977d4a400bd&to=c5e8738d4bfbf1e97e3f455fded90b791f223d74&stat=instructions:u |stage1-O3|stage1-ReleaseThinLTO|stage1-ReleaseLTO-g|stage1-O0-g|stage2-O3|stage2-O0-g|stage2-clang| |--|--|--|--|--|--|--| |+0.01%|+0.01%|-0.01%|+0.01%|+0.03%|-0.04%|+0.01%| The motivation of this patch is to reduce the number of `freeze` insts and enable more optimizations.
110 lines
3.7 KiB
LLVM
110 lines
3.7 KiB
LLVM
;; Test that pure virtual base is handled correctly.
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;; Index based WPD
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;; Generate unsplit module with summary for ThinLTO index-based WPD.
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; RUN: opt --thinlto-bc -o %t1a.o %s
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; RUN: llvm-lto2 run %t1a.o -save-temps -pass-remarks=. \
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; RUN: -whole-program-visibility \
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; RUN: -o %t3a \
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; RUN: -r=%t1a.o,_start,plx \
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; RUN: -r=%t1a.o,_ZTV1A,p \
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; RUN: -r=%t1a.o,_ZTV1B,p \
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; RUN: -r=%t1a.o,_ZN1A1fEi,p \
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; RUN: -r=%t1a.o,_ZN1A1nEi,p \
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; RUN: -r=%t1a.o,_ZN1B1fEi,p \
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; RUN: -r=%t1a.o,__cxa_pure_virtual, \
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; RUN: 2>&1 | FileCheck %s --check-prefix=REMARK
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; RUN: llvm-dis %t3a.1.4.opt.bc -o - | FileCheck %s --check-prefix=CHECK-IR
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;; Hybrid WPD
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;; Generate split module with summary for hybrid Thin/Regular LTO WPD.
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; RUN: opt --thinlto-bc --thinlto-split-lto-unit -o %t1b.o %s
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; RUN: llvm-lto2 run %t1b.o -save-temps -pass-remarks=. \
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; RUN: -whole-program-visibility \
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; RUN: -o %t3b \
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; RUN: -r=%t1b.o,_start,plx \
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; RUN: -r=%t1b.o,_ZTV1A, \
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; RUN: -r=%t1b.o,_ZTV1B, \
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; RUN: -r=%t1b.o,__cxa_pure_virtual, \
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; RUN: -r=%t1b.o,_ZN1A1fEi,p \
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; RUN: -r=%t1b.o,_ZN1A1nEi,p \
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; RUN: -r=%t1b.o,_ZN1B1fEi,p \
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; RUN: -r=%t1b.o,_ZTV1A,p \
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; RUN: -r=%t1b.o,_ZTV1B,p \
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; RUN: -r=%t1b.o,_ZN1A1nEi, \
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; RUN: -r=%t1b.o,_ZN1B1fEi, \
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; RUN: -r=%t1b.o,__cxa_pure_virtual, \
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; RUN: 2>&1 | FileCheck %s --check-prefix=REMARK
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; RUN: llvm-dis %t3b.1.4.opt.bc -o - | FileCheck %s --check-prefix=CHECK-IR
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;; Regular LTO WPD
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; RUN: opt -o %t1c.o %s
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; RUN: llvm-lto2 run %t1c.o -save-temps -pass-remarks=. \
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; RUN: -whole-program-visibility \
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; RUN: -o %t3c \
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; RUN: -r=%t1c.o,_start,plx \
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; RUN: -r=%t1c.o,_ZTV1A,p \
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; RUN: -r=%t1c.o,_ZTV1B,p \
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; RUN: -r=%t1c.o,_ZN1A1fEi,p \
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; RUN: -r=%t1c.o,_ZN1A1nEi,p \
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; RUN: -r=%t1c.o,_ZN1B1fEi,p \
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; RUN: -r=%t1c.o,__cxa_pure_virtual, \
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; RUN: 2>&1 | FileCheck %s --check-prefix=REMARK
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; RUN: llvm-dis %t3c.0.4.opt.bc -o - | FileCheck %s --check-prefix=CHECK-IR
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; REMARK-DAG: single-impl: devirtualized a call to _ZN1A1nEi
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target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-grtev4-linux-gnu"
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%struct.A = type { ptr }
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%struct.B = type { %struct.A }
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@_ZTV1A = linkonce_odr unnamed_addr constant { [4 x ptr] } { [4 x ptr] [ptr null, ptr undef, ptr @__cxa_pure_virtual, ptr @__cxa_pure_virtual] }, !type !0, !vcall_visibility !2
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@_ZTV1B = linkonce_odr unnamed_addr constant { [4 x ptr] } { [4 x ptr] [ptr null, ptr undef, ptr @_ZN1B1fEi, ptr @_ZN1A1nEi] }, !type !0, !type !1, !vcall_visibility !2
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;; Prevent the vtables from being dead code eliminated.
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@llvm.used = appending global [2 x ptr] [ ptr @_ZTV1A, ptr @_ZTV1B]
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; CHECK-IR-LABEL: define dso_local {{(noundef )?}}i32 @_start
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define i32 @_start(ptr %obj, i32 %a) {
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entry:
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%vtable = load ptr, ptr %obj
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%p = call i1 @llvm.type.test(ptr %vtable, metadata !"_ZTS1A")
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call void @llvm.assume(i1 %p)
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%fptrptr = getelementptr ptr, ptr %vtable, i32 1
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%fptr1 = load ptr, ptr %fptrptr, align 8
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;; Check that the call was devirtualized.
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; CHECK-IR: %call = tail call i32 @_ZN1A1nEi
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; CHECK-NODEVIRT-IR: %call = tail call i32 %fptr1
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%call = tail call i32 %fptr1(ptr nonnull %obj, i32 %a)
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ret i32 %call
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}
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; CHECK-IR-LABEL: ret i32
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; CHECK-IR-NEXT: }
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declare i1 @llvm.type.test(ptr, metadata)
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declare void @llvm.assume(i1)
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declare void @__cxa_pure_virtual() unnamed_addr
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define linkonce_odr i32 @_ZN1A1fEi(ptr %this, i32 %a) #0 {
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ret i32 0
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}
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define linkonce_odr i32 @_ZN1A1nEi(ptr %this, i32 %a) #0 {
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ret i32 0
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}
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define linkonce_odr i32 @_ZN1B1fEi(ptr %this, i32 %a) #0 {
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ret i32 0
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}
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;; Make sure we don't inline or otherwise optimize out the direct calls.
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attributes #0 = { noinline optnone }
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!0 = !{i64 16, !"_ZTS1A"}
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!1 = !{i64 16, !"_ZTS1B"}
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!2 = !{i64 0}
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