diff options
Diffstat (limited to 'lib/CodeGen/SimpleRegisterCoalescing.cpp')
| -rw-r--r-- | lib/CodeGen/SimpleRegisterCoalescing.cpp | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/lib/CodeGen/SimpleRegisterCoalescing.cpp b/lib/CodeGen/SimpleRegisterCoalescing.cpp index 41022a6e26..cfac82613f 100644 --- a/lib/CodeGen/SimpleRegisterCoalescing.cpp +++ b/lib/CodeGen/SimpleRegisterCoalescing.cpp @@ -119,6 +119,26 @@ bool SimpleRegisterCoalescing::AdjustCopiesBackFrom(LiveInterval &IntA, if (ALR == IntA.end()) // Should never happen! return false; VNInfo *AValNo = ALR->valno; + // If it's re-defined by an early clobber somewhere in the live range, then + // it's not safe to eliminate the copy. FIXME: This is a temporary workaround. + // See PR3149: + // 172 %ECX<def> = MOV32rr %reg1039<kill> + // 180 INLINEASM <es:subl $5,$1 + // sbbl $3,$0>, 10, %EAX<def>, 14, %ECX<earlyclobber,def>, 9, %EAX<kill>, + // 36, <fi#0>, 1, %reg0, 0, 9, %ECX<kill>, 36, <fi#1>, 1, %reg0, 0 + // 188 %EAX<def> = MOV32rr %EAX<kill> + // 196 %ECX<def> = MOV32rr %ECX<kill> + // 204 %ECX<def> = MOV32rr %ECX<kill> + // 212 %EAX<def> = MOV32rr %EAX<kill> + // 220 %EAX<def> = MOV32rr %EAX + // 228 %reg1039<def> = MOV32rr %ECX<kill> + // The early clobber operand ties ECX input to the ECX def. + // + // The live interval of ECX is represented as this: + // %reg20,inf = [46,47:1)[174,230:0) 0@174-(230) 1@46-(47) + // The coalescer has no idea there was a def in the middle of [174,230]. + if (AValNo->redefByEC) + return false; // If AValNo is defined as a copy from IntB, we can potentially process this. // Get the instruction that defines this value number. |