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Add a testcase for: 

void test(int N, double* G) {
  long j;
  for (j = 1; j < N - 1; j++)
      G[j] = G[j] + G[j+1] + G[j-1];
}

which we now compile to one load in the loop:

LBB1_2:                                                     ## %bb
	movsd	16(%rsi,%rax,8), %xmm2
	incq	%rdx
	addsd	%xmm2, %xmm1
	addsd	%xmm1, %xmm0
	movapd	%xmm2, %xmm1
	movsd	%xmm0, 8(%rsi,%rax,8)
	incq	%rax
	cmpq	%rcx, %rax
	jne	LBB1_2

instead of:

LBB1_2:                                                     ## %bb
	movsd	8(%rsi,%rax,8), %xmm0
	addsd	16(%rsi,%rax,8), %xmm0
	addsd	(%rsi,%rax,8), %xmm0
	movsd	%xmm0, 8(%rsi,%rax,8)
	incq	%rax
	cmpq	%rcx, %rax
	jne	LBB1_2

llvm-svn: 90048
This commit is contained in:
Chris Lattner 2009-11-29 01:15:43 +00:00
parent a73adac52e
commit 73d45454be
1 changed files with 47 additions and 0 deletions
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47
llvm/test/Transforms/GVN/pre-load.ll
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@ -314,3 +314,50 @@ return:
ret void
}
;void test10(int N, double* G) {
; long j;
; for (j = 1; j < N - 1; j++)
; G[j] = G[j] + G[j+1] + G[j-1];
;}
define void @test10(i32 %N, double* nocapture %G) nounwind ssp {
entry:
%0 = add i32 %N, -1
%1 = icmp sgt i32 %0, 1
br i1 %1, label %bb.nph, label %return
bb.nph:
%tmp = sext i32 %0 to i64
%tmp8 = add i64 %tmp, -1
br label %bb
; CHECK: bb.nph:
; CHECK: load double*
; CHECK: load double*
; CHECK: br label %bb
bb:
%indvar = phi i64 [ 0, %bb.nph ], [ %tmp11, %bb ]
%scevgep = getelementptr double* %G, i64 %indvar
%tmp9 = add i64 %indvar, 2
%scevgep10 = getelementptr double* %G, i64 %tmp9
%tmp11 = add i64 %indvar, 1
%scevgep12 = getelementptr double* %G, i64 %tmp11
%2 = load double* %scevgep12, align 8
%3 = load double* %scevgep10, align 8
%4 = fadd double %2, %3
%5 = load double* %scevgep, align 8
%6 = fadd double %4, %5
store double %6, double* %scevgep12, align 8
%exitcond = icmp eq i64 %tmp11, %tmp8
br i1 %exitcond, label %return, label %bb
; Should only be one load in the loop.
; CHECK: bb:
; CHECK: load double*
; CHECK-NOT: load double*
; CHECK: br i1 %exitcond
return:
ret void
}