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  1. Nov 27, 2009
  2. Nov 26, 2009
    • Chris Lattner's avatar
      Teach basicaa that x|c == x+c when the c bits of x are clear. This · 29bc8a91
      Chris Lattner authored
      allows us to compile the example in readme.txt into:
      
      LBB1_1:                                                     ## %bb
      	movl	4(%rdx,%rax), %ecx
      	movl	%ecx, %esi
      	imull	(%rdx,%rax), %esi
      	imull	%esi, %ecx
      	movl	%esi, 8(%rdx,%rax)
      	imull	%ecx, %esi
      	movl	%ecx, 12(%rdx,%rax)
      	movl	%esi, 16(%rdx,%rax)
      	imull	%ecx, %esi
      	movl	%esi, 20(%rdx,%rax)
      	addq	$16, %rax
      	cmpq	$4000, %rax
      	jne	LBB1_1
      
      instead of:
      
      LBB1_1: 
      	movl	(%rdx,%rax), %ecx
      	imull	4(%rdx,%rax), %ecx
      	movl	%ecx, 8(%rdx,%rax)
      	imull	4(%rdx,%rax), %ecx
      	movl	%ecx, 12(%rdx,%rax)
      	imull	8(%rdx,%rax), %ecx
      	movl	%ecx, 16(%rdx,%rax)
      	imull	12(%rdx,%rax), %ecx
      	movl	%ecx, 20(%rdx,%rax)
      	addq	$16, %rax
      	cmpq	$4000, %rax
      	jne	LBB1_1
      
      GCC (4.2) doesn't seem to be able to eliminate the loads in this 
      testcase either, it generates:
      
      L2:
      	movl	(%rdx), %eax
      	imull	4(%rdx), %eax
      	movl	%eax, 8(%rdx)
      	imull	4(%rdx), %eax
      	movl	%eax, 12(%rdx)
      	imull	8(%rdx), %eax
      	movl	%eax, 16(%rdx)
      	imull	12(%rdx), %eax
      	movl	%eax, 20(%rdx)
      	addl	$4, %ecx
      	addq	$16, %rdx
      	cmpl	$1002, %ecx
      	jne	L2
      
      llvm-svn: 89952
      29bc8a91
    • Chris Lattner's avatar
      teach basicaa that A[i] != A[i+1]. · 12dacdd3
      Chris Lattner authored
      llvm-svn: 89951
      12dacdd3
    • Chris Lattner's avatar
      update some notes slightly · 8e09ad6f
      Chris Lattner authored
      llvm-svn: 89913
      8e09ad6f
  3. Nov 25, 2009
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