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a4f468f245
We were calling llvm_unreachable() when failing to optimize the branch into if case. However, it is still possible for us to structurize the CFG by duplicating blocks even if this optimization fails. Reviewed-by: Vincent Lejeune<vljn at ovi.com> git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192813 91177308-0d34-0410-b5e6-96231b3b80d8
84 lines
2.2 KiB
LLVM
84 lines
2.2 KiB
LLVM
; RUN: llc < %s -march=r600 -mcpu=redwood | FileCheck %s
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; Test case for a crash in the AMDILCFGStructurizer from a CFG like this:
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;
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; entry
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; / \
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; diamond_head branch_from
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; / \ |
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; diamond_false diamond_true
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; \ /
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; done
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;
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; When the diamond_true branch had more than 100 instructions.
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;
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;
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; CHECK-LABEL: @branch_into_diamond
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; === entry block:
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; CHECK: ALU_PUSH_BEFORE
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; === Branch instruction (IF):
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; CHECK: JUMP
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; === branch_from block
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; CHECK: ALU
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; === Duplicated diamond_true block (There can be more than one ALU clause):
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; === XXX: We should be able to optimize this so the basic block is not
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; === duplicated. See comments in
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; === AMDGPUCFGStructurizer::improveSimpleJumpintoIf()
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; CHECK: ALU
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; === Branch instruction (ELSE):
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; CHECK: ELSE
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; === diamond_head block:
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; CHECK: ALU_PUSH_BEFORE
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; === Branch instruction (IF):
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; CHECK: JUMP
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; === diamond_true block (There can be more than one ALU clause):
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; ALU
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; === Branch instruction (ELSE):
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; CHECK: ELSE
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; === diamond_false block plus implicit ENDIF
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; CHECK: ALU_POP_AFTER
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; === Branch instruction (ENDIF):
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; CHECK: POP
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; === done block:
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; CHECK: ALU
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; CHECK: MEM_RAT_CACHELESS
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; CHECK: CF_END
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define void @branch_into_diamond(i32 addrspace(1)* %out, i32 %a, i32 %b, i32 %c) {
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entry:
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%0 = icmp ne i32 %a, 0
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br i1 %0, label %diamond_head, label %branch_from
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diamond_head:
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%1 = icmp ne i32 %a, 1
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br i1 %1, label %diamond_true, label %diamond_false
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branch_from:
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%2 = add i32 %a, 1
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br label %diamond_true
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diamond_false:
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%3 = add i32 %a, 2
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br label %done
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diamond_true:
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%4 = phi i32 [%2, %branch_from], [%a, %diamond_head]
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; This block needs to be > 100 ISA instructions to hit the bug,
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; so we'll use udiv instructions.
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%div0 = udiv i32 %a, %b
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%div1 = udiv i32 %div0, %4
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%div2 = udiv i32 %div1, 11
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%div3 = udiv i32 %div2, %a
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%div4 = udiv i32 %div3, %b
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%div5 = udiv i32 %div4, %c
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%div6 = udiv i32 %div5, %div0
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%div7 = udiv i32 %div6, %div1
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br label %done
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done:
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%5 = phi i32 [%3, %diamond_false], [%div7, %diamond_true]
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store i32 %5, i32 addrspace(1)* %out
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ret void
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}
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