mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-12-21 00:32:23 +00:00
3ef1aae2b5
This change teaches LazyValueInfo to use the @llvm.assume intrinsic. Like with
the known-bits change (r217342), this requires feeding a "context" instruction
pointer through many functions. Aside from a little refactoring to reuse the
logic that turns predicates into constant ranges in LVI, the only new code is
that which can 'merge' the range from an assumption into that otherwise
computed. There is also a small addition to JumpThreading so that it can have
LVI use assumptions in the same block as the comparison feeding a conditional
branch.
With this patch, we can now simplify this as expected:
int foo(int a) {
__builtin_assume(a > 5);
if (a > 3) {
bar();
return 1;
}
return 0;
}
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217345 91177308-0d34-0410-b5e6-96231b3b80d8
69 lines
1.8 KiB
LLVM
69 lines
1.8 KiB
LLVM
; RUN: opt -S -jump-threading -dce < %s | FileCheck %s
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target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-unknown-linux-gnu"
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; Function Attrs: nounwind uwtable
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define i32 @test1(i32 %a, i32 %b) #0 {
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entry:
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%cmp = icmp sgt i32 %a, 5
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tail call void @llvm.assume(i1 %cmp)
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%cmp1 = icmp sgt i32 %b, 1234
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br i1 %cmp1, label %if.then, label %if.else
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; CHECK-LABEL: @test1
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; CHECK: icmp sgt i32 %a, 5
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; CHECK: call void @llvm.assume
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; CHECK-NOT: icmp sgt i32 %a, 3
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; CHECK: ret i32
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if.then: ; preds = %entry
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%cmp2 = icmp sgt i32 %a, 3
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br i1 %cmp2, label %if.then3, label %return
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if.then3: ; preds = %if.then
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tail call void (...)* @bar() #1
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br label %return
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if.else: ; preds = %entry
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tail call void (...)* @car() #1
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br label %return
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return: ; preds = %if.else, %if.then, %if.then3
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%retval.0 = phi i32 [ 1, %if.then3 ], [ 0, %if.then ], [ 0, %if.else ]
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ret i32 %retval.0
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}
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define i32 @test2(i32 %a) #0 {
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entry:
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%cmp = icmp sgt i32 %a, 5
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tail call void @llvm.assume(i1 %cmp)
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%cmp1 = icmp sgt i32 %a, 3
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br i1 %cmp1, label %if.then, label %return
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; CHECK-LABEL: @test2
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; CHECK: icmp sgt i32 %a, 5
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; CHECK: tail call void @llvm.assume
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; CHECK: tail call void (...)* @bar()
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; CHECK: ret i32 1
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if.then: ; preds = %entry
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tail call void (...)* @bar() #1
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br label %return
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return: ; preds = %entry, %if.then
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%retval.0 = phi i32 [ 1, %if.then ], [ 0, %entry ]
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ret i32 %retval.0
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}
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; Function Attrs: nounwind
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declare void @llvm.assume(i1) #1
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declare void @bar(...)
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declare void @car(...)
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attributes #0 = { nounwind uwtable }
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attributes #1 = { nounwind }
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