[PATCH] D104692: [X86] Add a test to reveal a bug in CMOV conversion.

[Wang Tianqing via Phabricator via llvm-commits]

tianqing created this revision.
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CMOV conversion first rewrites all CMOVs with memory load to branches.
Then runs a second pass to convert other CMOVs in loops if profitable.
But the first pass doesn't add new basic blocks to MachineLoopInfo,
CMOVs in these blocks are ignored in the subsequent pass.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D104692

Files:
  llvm/test/CodeGen/X86/x86-cmov-converter.ll


Index: llvm/test/CodeGen/X86/x86-cmov-converter.ll
===================================================================
--- llvm/test/CodeGen/X86/x86-cmov-converter.ll
+++ llvm/test/CodeGen/X86/x86-cmov-converter.ll
@@ -483,4 +483,61 @@
   ret i32 %r
 }
 
+ at begin = external global i32*
+ at end = external global i32*
+
+define void @test_memoperand_loop(i32 %data) #0 {
+; CHECK-LABEL: test_memoperand_loop:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    movq begin at GOTPCREL(%rip), %r8
+; CHECK-NEXT:    movq (%r8), %rax
+; CHECK-NEXT:    movq end at GOTPCREL(%rip), %rcx
+; CHECK-NEXT:    movq (%rcx), %rdx
+; CHECK-NEXT:    xorl %esi, %esi
+; CHECK-NEXT:    movq %rax, %rcx
+entry:
+  %begin = load i32*, i32** @begin, align 8
+  %end = load i32*, i32** @end, align 8
+  br label %loop.body
+
+; CHECK-NEXT:  .LBB13_1: # %loop.body
+; CHECK-NEXT:    # =>This Inner Loop Header: Depth=1
+; CHECK-NEXT:    addq $8, %rcx
+; CHECK-NEXT:    cmpq %rdx, %rcx
+; CHECK-NEXT:    ja .LBB13_3
+; CHECK-NEXT:  # %bb.2: # %loop.body
+; CHECK-NEXT:    # in Loop: Header=BB13_1 Depth=1
+; CHECK-NEXT:    movq (%r8), %rcx
+; CHECK-NEXT:  .LBB13_3: # %loop.body
+; CHECK-NEXT:    # in Loop: Header=BB13_1 Depth=1
+; CHECK-NEXT:    movl %edi, (%rcx)
+; CHECK-NEXT:    addq $8, %rcx
+; CHECK-NEXT:    cmpq %rdx, %rcx
+; CHECK-NEXT:    cmovbeq %rax, %rcx
+; CHECK-NEXT:    movl %edi, (%rcx)
+; CHECK-NEXT:    addl $1, %esi
+; CHECK-NEXT:    cmpl $1024, %esi # imm = 0x400
+; CHECK-NEXT:    jl .LBB13_1
+loop.body:
+  %phi.iv = phi i32 [ 0, %entry ], [ %iv.next, %loop.body ]
+  %phi.ptr = phi i32* [ %begin, %entry ], [ %dst2, %loop.body ]
+  %gep1 = getelementptr inbounds i32, i32 *%phi.ptr, i64 2
+  %cmp1 = icmp ugt i32* %gep1, %end
+  %begin_dup = load i32*, i32** @begin, align 8
+  %dst1 = select i1 %cmp1, i32* %gep1, i32* %begin_dup
+  store i32 %data, i32 *%dst1, align 4
+  %gep2 = getelementptr inbounds i32, i32 *%dst1, i64 2
+  %cmp2 = icmp ugt i32* %gep2, %end
+  %dst2 = select i1 %cmp2, i32* %gep2, i32* %begin
+  store i32 %data, i32 *%dst2, align 4
+  %iv.next = add i32 %phi.iv, 1
+  %cond = icmp slt i32 %iv.next, 1024
+  br i1 %cond, label %loop.body, label %exit
+
+; CHECK-NEXT:  # %bb.4: # %exit
+; CHECK-NEXT:    retq
+exit:
+  ret void
+}
+
 attributes #0 = {"target-cpu"="x86-64"}


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