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https://github.com/c64scene-ar/llvm-6502.git
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d6ac8e9a03
latency for certain models of the Intel Atom family, by converting instructions into their equivalent LEA instructions, when it is both useful and possible to do so. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180573 91177308-0d34-0410-b5e6-96231b3b80d8
85 lines
2.5 KiB
LLVM
85 lines
2.5 KiB
LLVM
; RUN: llc < %s -mcpu=atom -mtriple=i686-linux | FileCheck %s
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; CHECK:BB#5
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; CHECK-NEXT:leal
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; CHECK-NEXT:leal
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; CHECK-NEXT:leal
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; CHECK-NEXT:movl
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; Test for fixup lea pre-emit pass. LEA instructions should be substituted for
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; ADD instructions which compute the address and index of the load because they
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; precede the load within 5 instructions. An LEA should also be substituted for
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; an ADD which computes part of the index because it precedes the index LEA
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; within 5 instructions, this substitution is referred to as backwards chaining.
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; Original C Code
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;struct node_t
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;{
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; int k, m, n, p;
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; int * array;
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;};
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;extern struct node_t getnode();
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;int test()
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;{
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; int sum = 0;
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; struct node_t n = getnode();
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; if(n.array != 0 && n.p > 0 && n.k > 0 && n.n > 0 && n.m > 0) {
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; sum = ((int*)((int)n.array + n.p) )[ n.k + n.m + n.n ];
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; }
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; return sum;
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;}
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%struct.node_t = type { i32, i32, i32, i32, i32* }
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define i32 @test() {
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entry:
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%n = alloca %struct.node_t, align 4
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call void bitcast (void (%struct.node_t*, ...)* @getnode to void (%struct.node_t*)*)(%struct.node_t* sret %n)
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%array = getelementptr inbounds %struct.node_t* %n, i32 0, i32 4
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%0 = load i32** %array, align 4
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%cmp = icmp eq i32* %0, null
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br i1 %cmp, label %if.end, label %land.lhs.true
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land.lhs.true:
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%p = getelementptr inbounds %struct.node_t* %n, i32 0, i32 3
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%1 = load i32* %p, align 4
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%cmp1 = icmp sgt i32 %1, 0
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br i1 %cmp1, label %land.lhs.true2, label %if.end
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land.lhs.true2:
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%k = getelementptr inbounds %struct.node_t* %n, i32 0, i32 0
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%2 = load i32* %k, align 4
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%cmp3 = icmp sgt i32 %2, 0
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br i1 %cmp3, label %land.lhs.true4, label %if.end
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land.lhs.true4:
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%n5 = getelementptr inbounds %struct.node_t* %n, i32 0, i32 2
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%3 = load i32* %n5, align 4
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%cmp6 = icmp sgt i32 %3, 0
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br i1 %cmp6, label %land.lhs.true7, label %if.end
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land.lhs.true7:
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%m = getelementptr inbounds %struct.node_t* %n, i32 0, i32 1
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%4 = load i32* %m, align 4
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%cmp8 = icmp sgt i32 %4, 0
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br i1 %cmp8, label %if.then, label %if.end
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if.then:
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%add = add i32 %3, %2
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%add12 = add i32 %add, %4
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%5 = ptrtoint i32* %0 to i32
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%add15 = add nsw i32 %1, %5
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%6 = inttoptr i32 %add15 to i32*
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%arrayidx = getelementptr inbounds i32* %6, i32 %add12
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%7 = load i32* %arrayidx, align 4
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br label %if.end
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if.end:
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%sum.0 = phi i32 [ %7, %if.then ], [ 0, %land.lhs.true7 ], [ 0, %land.lhs.true4 ], [ 0, %land.lhs.true2 ], [ 0, %land.lhs.true ], [ 0, %entry ]
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ret i32 %sum.0
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}
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declare void @getnode(%struct.node_t* sret, ...)
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