[llvm] Add -verify-with-context option to enable better reporting of verifier errors (PR #84867)

[Matt Arsenault via llvm-commits]

================
@@ -0,0 +1,31 @@
+; RUN: not opt -S %s -passes=verify -verify-with-context 2>&1 | FileCheck %s
+
+declare i32 @foo(i32)
+define i32 @test_callbr_landingpad_not_first_inst() {
+entry:
+  %0 = callbr i32 asm "", "=r,!i"()
+          to label %asm.fallthrough [label %landingpad]
+
+asm.fallthrough:
+  ret i32 42
+
+landingpad:
+  %foo = call i32 @foo(i32 42)
+; CHECK: Verification Error: No other instructions may proceed intrinsic
+; CHECK-NEXT: Verification Error: Context [Function 'test_callbr_landingpad_not_first_inst' -> BasicBlock 'landingpad' -> Instruction 'out' (number 2 inside BB)]
+; CHECK-NEXT: Context [Function 'test_callbr_landingpad_not_first_inst' -> BasicBlock 'landingpad']
+; CHECK-NEXT: %out = call i32 @llvm.callbr.landingpad.i32(i32 %0)
+  %out = call i32 @llvm.callbr.landingpad.i32(i32 %0)
+  ret i32 %out
+}
+
+declare <2 x double> @llvm.masked.load.v2f64.p0(ptr, i32, <2 x i1>, <2 x double>)
+
+define <2 x double> @masked_load(<2 x i1> %mask, ptr %addr, <2 x double> %dst) {
+; CHECK: Verification Error: masked_load: alignment must be a power of 2
+; CHECK-NEXT: Verification Error: Context [Function 'masked_load' -> BasicBlock '' -> Instruction 'res' (number 1 inside BB)]
+; CHECK-NEXT: Context [Function 'masked_load' -> BasicBlock '']
+; CHECK-NEXT: %res = call <2 x double> @llvm.masked.load.v2f64.p0(ptr %addr, i32 3, <2 x i1> %mask, <2 x double> %dst)
+  %res = call <2 x double> @llvm.masked.load.v2f64.p0(ptr %addr, i32 3, <2 x i1>%mask, <2 x double> %dst)
+  ret <2 x double> %res
+}
----------------
arsenm wrote:

Needs some tests with anonymous functions and blocks 

https://github.com/llvm/llvm-project/pull/84867