6afef286d9
Prior to this patch, the AVR::LDWRdPtr instruction was always lowered to
instructions of this pattern:
ld $GPR8, [PTR:XYZ]+
ld $GPR8, [PTR]+1
This has a problem; the [PTR] is incremented in-place once, but never
decremented.
Future uses of the same pointer will use the now clobbered value,
leading to the pointer being incorrect by an offset of one.
This patch modifies the expansion code of the LDWRdPtr pseudo
instruction so that the pointer variable is not silently clobbered in
future uses in the same live range.
Bug first reported by Keshav Kini.
Patch by Kaushik Phatak.
llvm-svn: 351673
30 lines
568 B
YAML
30 lines
568 B
YAML
# RUN: llc -O0 %s -o - | FileCheck %s
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# This test checks the expansion of the 16-bit LDWRdPtr pseudo instruction.
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--- |
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target triple = "avr--"
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define void @test_ldwrdptr() {
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entry:
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ret void
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}
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...
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---
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name: test_ldwrdptr
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tracksRegLiveness: true
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body: |
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bb.0.entry:
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; CHECK-LABEL: test_ldwrdptr
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; CHECK: ld [[SCRATCH:r[0-9]+]], Z
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; CHECK-NEXT: push [[SCRATCH]]
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; CHECK-NEXT: ldd [[SCRATCH]], Z+1
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; CHECK-NEXT: mov r31, [[SCRATCH]]
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; CHECK-NEXT: pop r30
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early-clobber $r31r30 = LDWRdPtr undef $r31r30
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...
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