0372768776
If a call argument has the "returned" attribute, we can simplify the call to the value of that argument. This was already partially handled by InstSimplify/InstCombine for the case where the argument is an integer constant, and the result is thus known via known bits. The non-constant (or non-int) argument cases weren't handled though. This previously landed as an InstSimplify transform, but was reverted due to assertion failures when compiling the Linux kernel. The reason is that simplifying a call to another call breaks assumptions in call graph updating during inlining. As the code is not easy to fix, and there is no particularly strong motivation for having this in InstSimplify, the transform is only performed in InstCombine instead. Differential Revision: https://reviews.llvm.org/D75815
78 lines
3.6 KiB
LLVM
78 lines
3.6 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; Test lib call simplification of __strncpy_chk calls with various values
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; for len and dstlen.
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;
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; RUN: opt < %s -instcombine -S | FileCheck %s
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target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
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@a = common global [60 x i8] zeroinitializer, align 1
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@b = common global [60 x i8] zeroinitializer, align 1
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@.str = private constant [12 x i8] c"abcdefghijk\00"
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; Check cases where dstlen >= len
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define i8* @test_simplify1() {
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; CHECK-LABEL: @test_simplify1(
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; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* nonnull align 1 dereferenceable(12) getelementptr inbounds ([60 x i8], [60 x i8]* @a, i32 0, i32 0), i8* nonnull align 1 dereferenceable(12) getelementptr inbounds ([12 x i8], [12 x i8]* @.str, i32 0, i32 0), i32 12, i1 false)
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; CHECK-NEXT: ret i8* getelementptr inbounds ([60 x i8], [60 x i8]* @a, i32 0, i32 0)
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;
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%dst = getelementptr inbounds [60 x i8], [60 x i8]* @a, i32 0, i32 0
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%src = getelementptr inbounds [12 x i8], [12 x i8]* @.str, i32 0, i32 0
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%ret = call i8* @__strncpy_chk(i8* %dst, i8* %src, i32 12, i32 60)
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ret i8* %ret
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}
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define i8* @test_simplify2() {
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; CHECK-LABEL: @test_simplify2(
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; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* nonnull align 1 dereferenceable(12) getelementptr inbounds ([60 x i8], [60 x i8]* @a, i32 0, i32 0), i8* nonnull align 1 dereferenceable(12) getelementptr inbounds ([12 x i8], [12 x i8]* @.str, i32 0, i32 0), i32 12, i1 false)
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; CHECK-NEXT: ret i8* getelementptr inbounds ([60 x i8], [60 x i8]* @a, i32 0, i32 0)
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;
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%dst = getelementptr inbounds [60 x i8], [60 x i8]* @a, i32 0, i32 0
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%src = getelementptr inbounds [12 x i8], [12 x i8]* @.str, i32 0, i32 0
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%ret = call i8* @__strncpy_chk(i8* %dst, i8* %src, i32 12, i32 12)
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ret i8* %ret
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}
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define i8* @test_simplify3() {
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; CHECK-LABEL: @test_simplify3(
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; CHECK-NEXT: [[STRNCPY:%.*]] = call i8* @strncpy(i8* nonnull dereferenceable(1) getelementptr inbounds ([60 x i8], [60 x i8]* @a, i32 0, i32 0), i8* nonnull dereferenceable(1) getelementptr inbounds ([60 x i8], [60 x i8]* @b, i32 0, i32 0), i32 12)
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; CHECK-NEXT: ret i8* getelementptr inbounds ([60 x i8], [60 x i8]* @a, i32 0, i32 0)
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;
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%dst = getelementptr inbounds [60 x i8], [60 x i8]* @a, i32 0, i32 0
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%src = getelementptr inbounds [60 x i8], [60 x i8]* @b, i32 0, i32 0
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%ret = call i8* @__strncpy_chk(i8* %dst, i8* %src, i32 12, i32 60)
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ret i8* %ret
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}
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; Check cases where dstlen < len
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define i8* @test_no_simplify1() {
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; CHECK-LABEL: @test_no_simplify1(
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; CHECK-NEXT: [[RET:%.*]] = call i8* @__strncpy_chk(i8* getelementptr inbounds ([60 x i8], [60 x i8]* @a, i32 0, i32 0), i8* getelementptr inbounds ([12 x i8], [12 x i8]* @.str, i32 0, i32 0), i32 8, i32 4)
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; CHECK-NEXT: ret i8* [[RET]]
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;
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%dst = getelementptr inbounds [60 x i8], [60 x i8]* @a, i32 0, i32 0
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%src = getelementptr inbounds [12 x i8], [12 x i8]* @.str, i32 0, i32 0
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%ret = call i8* @__strncpy_chk(i8* %dst, i8* %src, i32 8, i32 4)
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ret i8* %ret
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}
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define i8* @test_no_simplify2() {
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; CHECK-LABEL: @test_no_simplify2(
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; CHECK-NEXT: [[RET:%.*]] = call i8* @__strncpy_chk(i8* getelementptr inbounds ([60 x i8], [60 x i8]* @a, i32 0, i32 0), i8* getelementptr inbounds ([60 x i8], [60 x i8]* @b, i32 0, i32 0), i32 8, i32 0)
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; CHECK-NEXT: ret i8* [[RET]]
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;
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%dst = getelementptr inbounds [60 x i8], [60 x i8]* @a, i32 0, i32 0
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%src = getelementptr inbounds [60 x i8], [60 x i8]* @b, i32 0, i32 0
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%ret = call i8* @__strncpy_chk(i8* %dst, i8* %src, i32 8, i32 0)
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ret i8* %ret
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}
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declare i8* @__strncpy_chk(i8*, i8*, i32, i32)
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