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llvm-mirror/test/CodeGen/ARM/avoid-cpsr-rmw.ll
Andrew Trick 7b0a985247 Evict local live ranges if they can be reassigned.
The previous change to local live range allocation also suppressed
eviction of local ranges. In rare cases, this could result in more
expensive register choices. This commit actually revives a feature
that I added long ago: check if live ranges can be reassigned before
eviction. But now it only happens in rare cases of evicting a local
live range because another local live range wants a cheaper register.

The benefit is improved code size for some benchmarks on x86 and armv7.

I measured no significant compile time increase and performance
changes are noise.

llvm-svn: 187140
2013-07-25 18:35:19 +00:00

117 lines
3.8 KiB
LLVM

; RUN: llc < %s -mtriple=thumbv7-apple-darwin -mcpu=cortex-a9 | FileCheck %s
; RUN: llc < %s -mtriple=thumbv7-apple-darwin -mcpu=swift | FileCheck %s
; Avoid some 's' 16-bit instruction which partially update CPSR (and add false
; dependency) when it isn't dependent on last CPSR defining instruction.
; rdar://8928208
define i32 @t1(i32 %a, i32 %b, i32 %c, i32 %d) nounwind readnone {
entry:
; CHECK-LABEL: t1:
; CHECK: muls [[REG:(r[0-9]+)]], r3, r2
; CHECK-NEXT: mul [[REG2:(r[0-9]+)]], r1, r0
; CHECK-NEXT: muls r0, [[REG]], [[REG2]]
%0 = mul nsw i32 %a, %b
%1 = mul nsw i32 %c, %d
%2 = mul nsw i32 %0, %1
ret i32 %2
}
; Avoid partial CPSR dependency via loop backedge.
; rdar://10357570
define void @t2(i32* nocapture %ptr1, i32* %ptr2, i32 %c) nounwind {
entry:
; CHECK-LABEL: t2:
%tobool7 = icmp eq i32* %ptr2, null
br i1 %tobool7, label %while.end, label %while.body
while.body:
; CHECK: while.body
; CHECK: mul r{{[0-9]+}}
; CHECK-NOT: muls
%ptr1.addr.09 = phi i32* [ %add.ptr, %while.body ], [ %ptr1, %entry ]
%ptr2.addr.08 = phi i32* [ %incdec.ptr, %while.body ], [ %ptr2, %entry ]
%0 = load i32* %ptr1.addr.09, align 4
%arrayidx1 = getelementptr inbounds i32* %ptr1.addr.09, i32 1
%1 = load i32* %arrayidx1, align 4
%arrayidx3 = getelementptr inbounds i32* %ptr1.addr.09, i32 2
%2 = load i32* %arrayidx3, align 4
%arrayidx4 = getelementptr inbounds i32* %ptr1.addr.09, i32 3
%3 = load i32* %arrayidx4, align 4
%add.ptr = getelementptr inbounds i32* %ptr1.addr.09, i32 4
%mul = mul i32 %1, %0
%mul5 = mul i32 %mul, %2
%mul6 = mul i32 %mul5, %3
store i32 %mul6, i32* %ptr2.addr.08, align 4
%incdec.ptr = getelementptr inbounds i32* %ptr2.addr.08, i32 -1
%tobool = icmp eq i32* %incdec.ptr, null
br i1 %tobool, label %while.end, label %while.body
while.end:
ret void
}
; Allow partial CPSR dependency when code size is the priority.
; rdar://12878928
define void @t3(i32* nocapture %ptr1, i32* %ptr2, i32 %c) nounwind minsize {
entry:
; CHECK-LABEL: t3:
%tobool7 = icmp eq i32* %ptr2, null
br i1 %tobool7, label %while.end, label %while.body
while.body:
; CHECK: while.body
; CHECK: mul r{{[0-9]+}}
; CHECK: muls
%ptr1.addr.09 = phi i32* [ %add.ptr, %while.body ], [ %ptr1, %entry ]
%ptr2.addr.08 = phi i32* [ %incdec.ptr, %while.body ], [ %ptr2, %entry ]
%0 = load i32* %ptr1.addr.09, align 4
%arrayidx1 = getelementptr inbounds i32* %ptr1.addr.09, i32 1
%1 = load i32* %arrayidx1, align 4
%arrayidx3 = getelementptr inbounds i32* %ptr1.addr.09, i32 2
%2 = load i32* %arrayidx3, align 4
%arrayidx4 = getelementptr inbounds i32* %ptr1.addr.09, i32 3
%3 = load i32* %arrayidx4, align 4
%add.ptr = getelementptr inbounds i32* %ptr1.addr.09, i32 4
%mul = mul i32 %1, %0
%mul5 = mul i32 %mul, %2
%mul6 = mul i32 %mul5, %3
store i32 %mul6, i32* %ptr2.addr.08, align 4
%incdec.ptr = getelementptr inbounds i32* %ptr2.addr.08, i32 -1
%tobool = icmp eq i32* %incdec.ptr, null
br i1 %tobool, label %while.end, label %while.body
while.end:
ret void
}
; Avoid producing tMOVi8 after a high-latency flag-setting operation.
; <rdar://problem/13468102>
define void @t4(i32* nocapture %p, double* nocapture %q) {
entry:
; CHECK: t4
; CHECK: vmrs APSR_nzcv, fpscr
; CHECK: if.then
; CHECK-NOT: movs
%0 = load double* %q, align 4
%cmp = fcmp olt double %0, 1.000000e+01
%incdec.ptr1 = getelementptr inbounds i32* %p, i32 1
br i1 %cmp, label %if.then, label %if.else
if.then:
store i32 7, i32* %p, align 4
%incdec.ptr2 = getelementptr inbounds i32* %p, i32 2
store i32 8, i32* %incdec.ptr1, align 4
store i32 9, i32* %incdec.ptr2, align 4
br label %if.end
if.else:
store i32 3, i32* %p, align 4
%incdec.ptr5 = getelementptr inbounds i32* %p, i32 2
store i32 5, i32* %incdec.ptr1, align 4
store i32 6, i32* %incdec.ptr5, align 4
br label %if.end
if.end:
ret void
}