59 lines
		
	
	
		
			2.1 KiB
		
	
	
	
		
			LLVM
		
	
	
	
			
		
		
	
	
			59 lines
		
	
	
		
			2.1 KiB
		
	
	
	
		
			LLVM
		
	
	
	
; REQUIRES: x86-registered-target
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; RUN: opt -loop-reduce -S < %s | FileCheck %s
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; Strength reduction analysis here relies on IV Users analysis, that
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; only finds users among instructions with types that are treated as
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; legal by the data layout. When running this test on pure non-x86
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; configs (for example, ARM 64), it gets confused with the target
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; triple and uses a default data layout instead. This default layout
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; does not have any legal types (even i32), so the transformation
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; does not happen.
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target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
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target triple = "x86_64-apple-macosx"
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; PR15470: LSR miscompile. The test2 function should return '1'.
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;
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; SCEV expander cannot expand quadratic recurrences outside of the
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; loop. This recurrence depends on %sub.us, so can't be expanded.
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; We cannot fold SCEVUnknown (sub.us) with recurrences since it is
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; declared after the loop.
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;
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; CHECK-LABEL: @test2
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; CHECK-LABEL: test2.loop:
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; CHECK:  %lsr.iv1 = phi i32 [ %lsr.iv.next2, %test2.loop ], [ -16777216, %entry ]
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; CHECK:  %lsr.iv = phi i32 [ %lsr.iv.next, %test2.loop ], [ 1, %entry ]
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; CHECK:  %lsr.iv.next = add nsw i32 %lsr.iv, -1
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; CHECK:  %lsr.iv.next2 = add nsw i32 %lsr.iv1, 16777216
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;
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; CHECK-LABEL: for.end:
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; CHECK:  %tobool.us = icmp eq i32 %lsr.iv.next, 0
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; CHECK:  %sub.us = select i1 %tobool.us, i32 0, i32 0
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; CHECK:  %0 = sub i32 0, %sub.us
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; CHECK:  %1 = sub i32 %0, %lsr.iv.next
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; CHECK:  %sext.us = mul i32 %lsr.iv.next2, %1
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; CHECK:  %f = ashr i32 %sext.us, 24
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; CHECK: ret i32 %f
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define i32 @test2() {
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entry:
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  br label %test2.loop
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test2.loop:
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  %inc1115.us = phi i32 [ 0, %entry ], [ %inc11.us, %test2.loop ]
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  %inc11.us = add nsw i32 %inc1115.us, 1
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  %cmp.us = icmp slt i32 %inc11.us, 2
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  br i1 %cmp.us, label %test2.loop, label %for.end
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for.end:
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  %tobool.us = icmp eq i32 %inc1115.us, 0
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  %sub.us = select i1 %tobool.us, i32 0, i32 0
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  %mul.us = shl i32 %inc1115.us, 24
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  %sub.cond.us = sub nsw i32 %inc1115.us, %sub.us
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  %sext.us = mul i32 %mul.us, %sub.cond.us
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  %f = ashr i32 %sext.us, 24
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  br label %exit
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exit:
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  ret i32 %f
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}
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