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https://github.com/c64scene-ar/llvm-6502.git
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d84561bf69
In a previous iteration of the pass, we would try to compensate for writeback by updating later instructions and/or inserting a SUBS to reset the base register if necessary. Since such a SUBS sets the condition flags it's not generally safe to do this. For now, only merge LDR/STRs if there is no writeback to the base register (LDM that loads into the base register) or the base register is killed by one of the merged instructions. These cases are clear wins both in terms of instruction count and performance. Also add three new test cases, and update the existing ones accordingly. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215729 91177308-0d34-0410-b5e6-96231b3b80d8
41 lines
1.6 KiB
LLVM
41 lines
1.6 KiB
LLVM
; RUN: llc -mtriple=thumbv6m-eabi -verify-machineinstrs %s -o - | FileCheck %s
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target datalayout = "e-m:e-p:32:32-i1:8:32-i8:8:32-i16:16:32-i64:64-v128:64:128-a:0:32-n32-S64"
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target triple = "thumbv6m--linux-gnueabi"
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@d = internal unnamed_addr global i32 0, align 4
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@c = internal global i32* null, align 4
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@e = internal unnamed_addr global i32* null, align 4
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; Function Attrs: nounwind optsize
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define void @fn1() #0 {
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entry:
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; CHECK-LABEL: fn1:
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; CHECK: stm r[[BASE:[0-9]]]!, {{.*}}
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; CHECK-NOT: {{.*}} r[[BASE]]
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; CHECK: ldr r[[BASE]], {{.*}}
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%g = alloca i32, align 4
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%h = alloca i32, align 4
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store i32 1, i32* %g, align 4
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store i32 0, i32* %h, align 4
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%.pr = load i32* @d, align 4
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%cmp11 = icmp slt i32 %.pr, 1
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br i1 %cmp11, label %for.inc.lr.ph, label %for.body5
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for.inc.lr.ph: ; preds = %entry
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store i32 1, i32* @d, align 4
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br label %for.body5
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for.body5: ; preds = %entry, %for.inc.lr.ph, %for.body5
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%f.010 = phi i32 [ %inc7, %for.body5 ], [ 0, %for.inc.lr.ph ], [ 0, %entry ]
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store volatile i32* %g, i32** @c, align 4
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%inc7 = add nsw i32 %f.010, 1
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%exitcond = icmp eq i32 %inc7, 2
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br i1 %exitcond, label %for.end8, label %for.body5
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for.end8: ; preds = %for.body5
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store i32* %h, i32** @e, align 4
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ret void
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}
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attributes #0 = { nounwind optsize "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
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