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7f44c8f183
Constants are crucial for code size in the ARM Thumb-1 instruction set. The 16 bit instruction size often does not offer enough space for immediate arguments. This means that additional instructions are frequently used to load constants into registers. Since constants are hoisted, this can lead to significant register spillage if they are used multiple times in a single function. This can be avoided by rematerialization, i.e. recomputing a constant instead of reloading it from the stack. This patch fixes the rematerialization of literal pool loads in the ARM Thumb instruction set. Patch by Philip Ginsbach Differential Revision: https://reviews.llvm.org/D33936 llvm-svn: 308004
29 lines
814 B
LLVM
29 lines
814 B
LLVM
; RUN: llc < %s -mtriple=thumb-apple-darwin | FileCheck %s
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declare void @consume_value(i32) #1
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declare i32 @get_value(...) #1
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declare void @consume_three_values(i32, i32, i32) #1
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; Function Attrs: nounwind uwtable
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define void @should_not_spill() #0 {
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tail call void @consume_value(i32 1764) #2
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%1 = tail call i32 (...) @get_value() #2
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%2 = tail call i32 (...) @get_value() #2
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%3 = tail call i32 (...) @get_value() #2
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tail call void @consume_value(i32 %1) #2
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tail call void @consume_value(i32 %2) #2
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tail call void @consume_value(i32 %3) #2
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tail call void @consume_value(i32 1764) #2
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tail call void @consume_three_values(i32 %1, i32 %2, i32 %3) #2
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ret void
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}
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; CHECK: ldr r0, LCPI0_0
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; CHECK-NOT: str r0
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; CHECK: bl
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; CHECK: ldr r0, LCPI0_0
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; CHECK-LABEL: LCPI0_0:
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; CHECK-NEXT: .long 1764
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