[clang] [llvm] [AVR] Fix Avr indvar detection and strength reduction (missed optimization) (PR #152028)

[Ben Shi via llvm-commits]

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@@ -112,8 +114,11 @@ while.end:                                        ; preds = %while.body, %entry
 
 define void @store16predec(ptr %x, i16 %y) {
 ; CHECK-LABEL: store16predec:
-; CHECK: st -{{[XYZ]}}, {{.*}}
-; CHECK: st -{{[XYZ]}}, {{.*}}
+; TODO: st -{{[XYZ]}}, {{.*}}
+; TODO: st -{{[XYZ]}}, {{.*}}
+; CHECK: sbiw {{..*}}, 2
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benshi001 wrote:

Or just as [Patryk27](https://github.com/Patryk27) indicated, just using the exact register for `sbiw` and `ld`, instead of regexp pattern. My key concern is it should show the relationship between sbiw and ld/st.

https://github.com/llvm/llvm-project/pull/152028