69 lines
3.1 KiB
LLVM
69 lines
3.1 KiB
LLVM
; RUN: llc -verify-machineinstrs -mtriple=powerpc-unknown-linux-gnu -mattr=+altivec < %s | FileCheck %s
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;; This test ensures that MergeConsecutiveStores does not attempt to
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;; merge stores or loads when doing so would result in unaligned
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;; memory operations (unless the target supports those, e.g. X86).
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;; This issue happen in other situations for other targets, but PPC
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;; with Altivec extensions was chosen for the test because it does not
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;; support unaligned access with AltiVec instructions. If the 4
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;; load/stores get merged to an v4i32 vector type severely bad code
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;; gets generated: it painstakingly copies the values to a temporary
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;; location on the stack, with vector ops, in order to then use
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;; integer ops to load from the temporary stack location and store to
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;; the final location. Yuck!
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%struct.X = type { i32, i32, i32, i32 }
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@fx = common global %struct.X zeroinitializer, align 4
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@fy = common global %struct.X zeroinitializer, align 4
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;; In this test case, lvx and stvx instructions should NOT be
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;; generated, as the alignment is not sufficient for it to be
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;; worthwhile.
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;; CHECK-LABEL: f:
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;; CHECK-DAG: lwzu
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;; CHECK-DAG: stwu
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;; CHECK-DAG: lwz
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;; CHECK-DAG: lwz
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;; CHECK-DAG: lwz
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;; CHECK-DAG: stw
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;; CHECK-DAG: stw
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;; CHECK-DAG: stw
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;; CHECK-NEXT: blr
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define void @f() {
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entry:
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%0 = load i32, i32* getelementptr inbounds (%struct.X, %struct.X* @fx, i32 0, i32 0), align 4
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%1 = load i32, i32* getelementptr inbounds (%struct.X, %struct.X* @fx, i32 0, i32 1), align 4
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%2 = load i32, i32* getelementptr inbounds (%struct.X, %struct.X* @fx, i32 0, i32 2), align 4
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%3 = load i32, i32* getelementptr inbounds (%struct.X, %struct.X* @fx, i32 0, i32 3), align 4
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store i32 %0, i32* getelementptr inbounds (%struct.X, %struct.X* @fy, i32 0, i32 0), align 4
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store i32 %1, i32* getelementptr inbounds (%struct.X, %struct.X* @fy, i32 0, i32 1), align 4
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store i32 %2, i32* getelementptr inbounds (%struct.X, %struct.X* @fy, i32 0, i32 2), align 4
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store i32 %3, i32* getelementptr inbounds (%struct.X, %struct.X* @fy, i32 0, i32 3), align 4
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ret void
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}
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@gx = common global %struct.X zeroinitializer, align 16
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@gy = common global %struct.X zeroinitializer, align 16
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;; In this test, lvx and stvx instructions SHOULD be generated, as
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;; the 16-byte alignment of the new load/store is acceptable.
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;; CHECK-LABEL: g:
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;; CHECK: lvx
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;; CHECK: stvx
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;; CHECK: blr
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define void @g() {
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entry:
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%0 = load i32, i32* getelementptr inbounds (%struct.X, %struct.X* @fx, i32 0, i32 0), align 16
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%1 = load i32, i32* getelementptr inbounds (%struct.X, %struct.X* @fx, i32 0, i32 1), align 4
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%2 = load i32, i32* getelementptr inbounds (%struct.X, %struct.X* @fx, i32 0, i32 2), align 4
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%3 = load i32, i32* getelementptr inbounds (%struct.X, %struct.X* @fx, i32 0, i32 3), align 4
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store i32 %0, i32* getelementptr inbounds (%struct.X, %struct.X* @fy, i32 0, i32 0), align 16
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store i32 %1, i32* getelementptr inbounds (%struct.X, %struct.X* @fy, i32 0, i32 1), align 4
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store i32 %2, i32* getelementptr inbounds (%struct.X, %struct.X* @fy, i32 0, i32 2), align 4
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store i32 %3, i32* getelementptr inbounds (%struct.X, %struct.X* @fy, i32 0, i32 3), align 4
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ret void
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}
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