Hongtao Yu
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911e06f5eb
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[ICP] Handling must tail calls in indirect call promotion
Per the IR convention, a musttail call must precede a ret with an optional bitcast. This was violated by the indirect call promotion optimization which could result an IR like:
; <label>:2192:
br i1 %2198, label %2199, label %2201, !dbg !226012, !prof !229483
; <label>:2199: ; preds = %2192
musttail call fastcc void @foo(i8* %2195), !dbg !226012
br label %2202, !dbg !226012
; <label>:2201: ; preds = %2192
musttail call fastcc void %2197(i8* %2195), !dbg !226012
br label %2202, !dbg !226012
; <label>:2202: ; preds = %605, %2201, %2199
ret void, !dbg !229485
This is being fixed in this change where the return statement goes together with the promoted indirect call. The code generated is like:
; <label>:2192:
br i1 %2198, label %2199, label %2201, !dbg !226012, !prof !229483
; <label>:2199: ; preds = %2192
musttail call fastcc void @foo(i8* %2195), !dbg !226012
ret void, !dbg !229485
; <label>:2201: ; preds = %2192
musttail call fastcc void %2197(i8* %2195), !dbg !226012
ret void, !dbg !229485
Differential Revision: https://reviews.llvm.org/D79258
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2020-05-03 10:42:22 -07:00 |