forked from OSchip/llvm-project
79 lines
2.4 KiB
LLVM
79 lines
2.4 KiB
LLVM
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; RUN: llc < %s -march=avr | FileCheck %s
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; This tests how LLVM handles IR which puts very high
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; presure on the PTRREGS class for the register allocator.
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;
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; This causes a problem because we only have one small register
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; class for loading and storing from pointers - 'PTRREGS'.
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; One of these registers is also used for the frame pointer, meaning
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; that we only ever have two registers available for these operations.
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;
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; There is an existing bug filed for this issue - PR14879.
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;
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; The specific failure:
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; LLVM ERROR: ran out of registers during register allocation
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;
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; It has been assembled from the following c code:
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;
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; struct ss
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; {
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; int a;
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; int b;
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; int c;
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; };
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;
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; void loop(struct ss *x, struct ss **y, int z)
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; {
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; int i;
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; for (i=0; i<z; ++i)
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; {
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; x->c += y[i]->b;
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; }
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; }
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%struct.ss = type { i16, i16, i16 }
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; CHECK-LABEL: loop
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define void @loop(%struct.ss* %x, %struct.ss** %y, i16 %z) #0 {
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entry:
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%x.addr = alloca %struct.ss*, align 2
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%y.addr = alloca %struct.ss**, align 2
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%z.addr = alloca i16, align 2
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%i = alloca i16, align 2
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store %struct.ss* %x, %struct.ss** %x.addr, align 2
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store %struct.ss** %y, %struct.ss*** %y.addr, align 2
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store i16 %z, i16* %z.addr, align 2
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store i16 0, i16* %i, align 2
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br label %for.cond
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for.cond: ; preds = %for.inc, %entry
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%tmp = load i16, i16* %i, align 2
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%tmp1 = load i16, i16* %z.addr, align 2
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%cmp = icmp slt i16 %tmp, %tmp1
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br i1 %cmp, label %for.body, label %for.end
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for.body: ; preds = %for.cond
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%tmp2 = load %struct.ss**, %struct.ss*** %y.addr, align 2
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%tmp3 = load i16, i16* %i, align 2
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%arrayidx = getelementptr inbounds %struct.ss*, %struct.ss** %tmp2, i16 %tmp3
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%tmp4 = load %struct.ss*, %struct.ss** %arrayidx, align 2
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%b = getelementptr inbounds %struct.ss, %struct.ss* %tmp4, i32 0, i32 1
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%tmp5 = load i16, i16* %b, align 2
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%tmp6 = load %struct.ss*, %struct.ss** %x.addr, align 2
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%c = getelementptr inbounds %struct.ss, %struct.ss* %tmp6, i32 0, i32 2
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%tmp7 = load i16, i16* %c, align 2
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%add = add nsw i16 %tmp7, %tmp5
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store i16 %add, i16* %c, align 2
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br label %for.inc
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for.inc: ; preds = %for.body
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%tmp8 = load i16, i16* %i, align 2
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%inc = add nsw i16 %tmp8, 1
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store i16 %inc, i16* %i, align 2
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br label %for.cond
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for.end: ; preds = %for.cond
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ret void
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}
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