llvm-6502/test/CodeGen/ARM/avoid-cpsr-rmw.ll
Jakob Stoklund Olesen ee27cac9fa Avoid high-latency false CPSR dependencies even for tMOVSi.
The Thumb2SizeReduction pass avoids false CPSR dependencies, except it
still aggressively creates tMOVi8 instructions because they are so
common.

Avoid creating false CPSR dependencies even for tMOVi8 instructions when
the the CPSR flags are known to have high latency. This allows integer
computation to overlap floating point computations.

Also process blocks in a reverse post-order and propagate high-latency
flags to successors.

<rdar://problem/13468102>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178773 91177308-0d34-0410-b5e6-96231b3b80d8
2013-04-04 18:25:36 +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: 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: 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: 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
}