1376301c87
InstCombine converts range tests of the form (X > C1 && X < C2) or (X < C1 || X > C2) into checks of the form (X + C3 < C4) or (X + C3 > C4). It is possible to express all range tests in either of these forms (with different choices of constants), but currently neither of them is considered canonical. We may have equivalent range tests using either ult or ugt. This proposes to canonicalize all range tests to use ult. An alternative would be to canonicalize to either ult or ugt depending on the specific constants involved -- e.g. in practice we currently generate ult for && style ranges and ugt for || style ranges when going through the insertRangeTest() helper. In fact, the "clamp like" fold was relying on this, which is why I had to tweak it to not assume whether inversion is needed based on just the predicate. Proof: https://alive2.llvm.org/ce/z/_SP_rQ Differential Revision: https://reviews.llvm.org/D113366
99 lines
3.7 KiB
LLVM
99 lines
3.7 KiB
LLVM
; RUN: opt -O2 -mtriple=bpf-pc-linux %s | llvm-dis > %t1
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; RUN: llc %t1 -o - | FileCheck -check-prefixes=CHECK %s
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; RUN: opt -O2 -mtriple=bpf-pc-linux -bpf-disable-serialize-icmp %s | llvm-dis > %t1
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; RUN: llc %t1 -o - | FileCheck -check-prefixes=CHECK-DISABLE %s
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;
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; Source:
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; int foo();
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; int bar(int);
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; int test() {
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; int ret = foo();
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; if (ret <= 0)
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; return 0;
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; if (ret > 7)
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; return 0;
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; return bar(ret);
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; }
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; Compilation flag:
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; clang -target bpf -O2 -S -emit-llvm -Xclang -disable-llvm-passes test.c
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; Function Attrs: nounwind
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define dso_local i32 @test() #0 {
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entry:
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%retval = alloca i32, align 4
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%ret = alloca i32, align 4
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%cleanup.dest.slot = alloca i32, align 4
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%0 = bitcast i32* %ret to i8*
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call void @llvm.lifetime.start.p0i8(i64 4, i8* %0) #3
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%call = call i32 bitcast (i32 (...)* @foo to i32 ()*)()
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store i32 %call, i32* %ret, align 4, !tbaa !2
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%1 = load i32, i32* %ret, align 4, !tbaa !2
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%cmp = icmp sle i32 %1, 0
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br i1 %cmp, label %if.then, label %if.end
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; CHECK: [[REG1:r[0-9]+]] <<= 32
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; CHECK: [[REG1]] s>>= 32
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; CHECK: [[REG2:r[0-9]+]] = 1
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; CHECK: if [[REG2]] s> [[REG1]] goto
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; CHECK: if [[REG1]] s> 7 goto
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; CHECK-DISABLE: [[REG1:r[0-9]+]] += -8
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; CHECK-DISABLE: [[REG1]] <<= 32
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; CHECK-DISABLE: [[REG1]] >>= 32
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; CHECK-DISABLE: [[REG2:r[0-9]+]] = 4294967289
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; CHECK-DISABLE: if [[REG2]] > [[REG1]] goto
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if.then: ; preds = %entry
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store i32 0, i32* %retval, align 4
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store i32 1, i32* %cleanup.dest.slot, align 4
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br label %cleanup
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if.end: ; preds = %entry
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%2 = load i32, i32* %ret, align 4, !tbaa !2
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%cmp1 = icmp sgt i32 %2, 7
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br i1 %cmp1, label %if.then2, label %if.end3
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if.then2: ; preds = %if.end
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store i32 0, i32* %retval, align 4
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store i32 1, i32* %cleanup.dest.slot, align 4
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br label %cleanup
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if.end3: ; preds = %if.end
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%3 = load i32, i32* %ret, align 4, !tbaa !2
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%call4 = call i32 @bar(i32 %3)
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store i32 %call4, i32* %retval, align 4
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store i32 1, i32* %cleanup.dest.slot, align 4
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br label %cleanup
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cleanup: ; preds = %if.end3, %if.then2, %if.then
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%4 = bitcast i32* %ret to i8*
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call void @llvm.lifetime.end.p0i8(i64 4, i8* %4) #3
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%5 = load i32, i32* %retval, align 4
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ret i32 %5
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}
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; Function Attrs: argmemonly nounwind willreturn
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declare void @llvm.lifetime.start.p0i8(i64 immarg, i8* nocapture) #1
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declare dso_local i32 @foo(...) #2
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declare dso_local i32 @bar(i32) #2
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; Function Attrs: argmemonly nounwind willreturn
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declare void @llvm.lifetime.end.p0i8(i64 immarg, i8* nocapture) #1
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attributes #0 = { nounwind "disable-tail-calls"="false" "frame-pointer"="all" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
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attributes #1 = { argmemonly nounwind willreturn }
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attributes #2 = { "disable-tail-calls"="false" "frame-pointer"="all" "less-precise-fpmad"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
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attributes #3 = { nounwind }
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!llvm.module.flags = !{!0}
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!llvm.ident = !{!1}
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!0 = !{i32 1, !"wchar_size", i32 4}
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!1 = !{!"clang version 12.0.0 (https://github.com/llvm/llvm-project.git ca9c5433a6c31e372092fcd8bfd0e4fddd7e8784)"}
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!2 = !{!3, !3, i64 0}
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!3 = !{!"int", !4, i64 0}
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!4 = !{!"omnipotent char", !5, i64 0}
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!5 = !{!"Simple C/C++ TBAA"}
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