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809b1c325f
Currently, a load from an alloca that is used in as single block and is not preceded by a store is replaced by undef. This is not always correct if the single block is inside a loop. Fix the logic so that: 1) If there are no stores in the block, replace the load with an undef, as before. 2) If there is a store (regardless of where it is in the block w.r.t the load), bail out, and let the rest of mem2reg handle this alloca. Patch by: gil.rapaport@intel.com Differential Revision: http://reviews.llvm.org/D11355 llvm-svn: 242884
45 lines
974 B
LLVM
45 lines
974 B
LLVM
; RUN: opt -mem2reg < %s -S | FileCheck %s
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declare i32 @def(i32)
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declare i1 @use(i32)
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; Special case of a single-BB alloca does not apply here since the load
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; is affected by the following store. Expect this case to be identified
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; and a PHI node to be created.
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define void @test1() {
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; CHECK-LABEL: @test1(
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entry:
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%t = alloca i32
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br label %loop
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loop:
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%v = load i32, i32* %t
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%c = call i1 @use(i32 %v)
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; CHECK: [[PHI:%.*]] = phi i32 [ undef, %entry ], [ %n, %loop ]
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; CHECK: call i1 @use(i32 [[PHI]])
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%n = call i32 @def(i32 7)
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store i32 %n, i32* %t
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br i1 %c, label %loop, label %exit
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exit:
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ret void
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}
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; Same as above, except there is no following store. The alloca should just be
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; replaced with an undef
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define void @test2() {
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; CHECK-LABEL: @test2(
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entry:
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%t = alloca i32
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br label %loop
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loop:
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%v = load i32, i32* %t
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%c = call i1 @use(i32 %v)
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; CHECK: %c = call i1 @use(i32 undef)
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br i1 %c, label %loop, label %exit
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exit:
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ret void
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}
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