7faf1a0868
This patch adds a pass that provides workarounds for the errata described in GRLIB-TN-0009, GRLIB-TN-0010, GRLIB-TN-0011, GRLIB-TN-0012, and GRLIB-TN-0013, that are applicable to the GR712RC and UT700. The documents are available for download from here: https://www.gaisler.com/index.php/information/app-tech-notes The pass will detect certain sensitive instruction sequences and prevent them from occurring by inserting NOP instruction. Below is an overview of each of the workarounds. A similar implementation is available in GCC. GRLIB-TN-0009: * Insert NOPs to prevent the sequence (stb/sth/st/stf) -> (single non-store/load instruction) -> (any store) * Insert NOPs to prevent the sequence (std/stdf) -> (any store) GRLIB-TN-0010: * Insert a NOP between load instruction and atomic instruction (swap and casa). * Insert a NOP at branch target if load in delay slot and atomic instruction at branch target. * Do not allow functions to begin with atomic instruction. GRLIB-TN-0011: * Insert .p2align 4 before atomic instructions (swap and casa). GRLIB-TN-0012: * Place a NOP at the branch target of an integer branch if it is a floating-point operation or a floating-point branch. GRLIB-TN-0013: * Prevent (div/sqrt) instructions in the delay slot. * Insert NOPs to prevent the sequence (div/sqrt) -> (two or three floating point operations or loads) -> (div/sqrt). * Do not insert NOPs if any of the floating point operations have a dependency on the destination register of the first (div/sqrt). * Do not insert NOPs if one of the floating point operations is a (div/sqrt). * Insert NOPs to prevent (div/sqrt) followed by a branch.
66 lines
1.1 KiB
YAML
66 lines
1.1 KiB
YAML
# RUN: llc %s -mattr=+fix-tn0012 -march=sparc -run-pass=errata-workaround -o - \
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# RUN: | FileCheck %s
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---
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# CHECK: bb.2:
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# CHECK: NOP
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# CHECK-NEXT: $f0 = FADDS $f0, $f0
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name: er-5-1
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body: |
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bb.0.entry:
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successors: %bb.1, %bb.2
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BCOND %bb.2, 10, implicit $icc {
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NOP
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}
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bb.1.entry:
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successors: %bb.2
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NOP
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bb.2:
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$f0 = FADDS $f0, $f0
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---
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# CHECK: bb.2:
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# CHECK: NOP
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# CHECK-NEXT: FBCOND %bb.3, 22, implicit $fcc0 {
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name: er-5-2
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body: |
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bb.0.entry:
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successors: %bb.2, %bb.1
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BCOND %bb.1, 10, implicit $icc {
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NOP
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}
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bb.2.entry:
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successors: %bb.1
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NOP
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bb.1:
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successors: %bb.3
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FBCOND %bb.3, 22, implicit $fcc0 {
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NOP
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}
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bb.3:
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NOP
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---
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# CHECK: bb.2:
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# CHECK: NOP
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# CHECK-NEXT: FCMPS $f0, $f0, implicit-def $fcc0
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name: er-5-3
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body: |
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bb.0.entry:
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successors: %bb.1, %bb.2
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BCOND %bb.2, 10, implicit $icc {
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NOP
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}
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bb.1.entry:
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successors: %bb.2
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NOP
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bb.2:
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FCMPS $f0, $f0, implicit-def $fcc0
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...
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