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	If we have an add (or an or that is really an add), where one operand is a
FrameIndex and the other operand is a small constant, we can combine the
lowering of the FrameIndex (which is lowered as an add of the FI and a zero
offset) with the constant operand.
Amusingly, this is an old potential improvement entry from
lib/Target/PowerPC/README.txt which had never been resolved. In short, we used
to lower:
        %X = alloca { i32, i32 }
        %Y = getelementptr {i32,i32}* %X, i32 0, i32 1
        ret i32* %Y
as:
        addi 3, 1, -8
        ori 3, 3, 4
        blr
and now we produce:
        addi 3, 1, -4
        blr
which is much more sensible.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224071 91177308-0d34-0410-b5e6-96231b3b80d8
		
	
		
			
				
	
	
		
			25 lines
		
	
	
		
			536 B
		
	
	
	
		
			LLVM
		
	
	
	
	
	
			
		
		
	
	
			25 lines
		
	
	
		
			536 B
		
	
	
	
		
			LLVM
		
	
	
	
	
	
| ; RUN: llc -mcpu=ppc64 < %s | FileCheck %s
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| target datalayout = "E-m:e-i64:64-n32:64"
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| target triple = "powerpc64-unknown-linux-gnu"
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| 
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| define i32* @test1() {
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|         %X = alloca { i32, i32 }
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|         %Y = getelementptr {i32,i32}* %X, i32 0, i32 1
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|         ret i32* %Y
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| 
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| ; CHECK-LABEL: @test1
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| ; CHECK: addi 3, 1, -4
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| ; CHECK: blr
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| }
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| 
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| define i32* @test2() {
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|         %X = alloca { i32, i32, i32, i32 }
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|         %Y = getelementptr {i32,i32,i32,i32}* %X, i32 0, i32 3
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|         ret i32* %Y
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| 
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| ; CHECK-LABEL: @test2
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| ; CHECK: addi 3, 1, -4
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| ; CHECK: blr
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| }
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| 
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